Defenses Available Under the Australian Criminal Justice System

There are a number of valid legal defences that are available to defendants, in the event that they are charged with a criminal offence. This article is intended to provide a simple guide to defendants about the most commonly used legal defences in New South Wales, particularly at local court level, as well as a basic explanation of the legal requirements for these defences.

Self defence or defence of another

In matters involving assault, homicide or any other offences involving the use of force, defendants may rely upon the legal defence of self-defence, or defence of another. Once the issue of self-defence is raised, the burden is then placed on the prosecution to prove that the defendant was not acting in self-defence, beyond the standard of reasonable doubt. Because self-defence is a complete defence, if it is accepted by the court it must dismiss the charges against the defendant. Under section 418 of the Crimes Act 1900 (NSW), defendants are not criminally responsible for an offence where they believe that their actions were necessary:

(a) to defend themselves or another person, or

(b) to prevent or terminate the unlawful deprivation of their or another person’s liberty, or

(c) to protect property from unlawful taking, destruction, damage or interference, or

(d) to prevent criminal trespass or to remove a person trespassing on any property

and that the conduct was a reasonable response in the circumstances as they perceived them.

From this section, it should be noted that the two most important elements of the test for self-defence, are its subjective and objective requirements. The subjective component is that the defendant must have believed at the time they committed the offence that their actions were necessary. Because this is a subjective test, it ignores what a reasonable person in the same circumstances would have done, instead determining whether the defendant was convinced their actions were necessary. It is therefore irrelevant whether the defendant’s beliefs were erroneous or not, as the only requirement is that their beliefs were genuinely held. The objective component is that the defendant’s actions must have been reasonable in the circumstances. The court will objectively assess the proportionality of the defendant’s response to the situation, and will not take into account whether the defendant was of the belief that they were acting reasonably. The prosecution must prove beyond reasonable doubt that at least one of these elements was not present in the offence, or otherwise the defendant will be entitled to an acquittal.


Another defence which may be used by a defendant charged with a criminal offence, is that of duress. A defendant may claim that they acted under duress if their actions were motivated by a serious threat against them or their family, and serious injury or death would have resulted if they did not perform the criminal act. In order to be eligible for the duress defence, the circumstances must have been so severe for the defendant that their will was in effect constrained completely, forcing them to be a mere innocent instrument of the crime. Some of the requirements for establishing a defence of duress were set out by Chief Justice Hunt at CL in Bassett (1994), an unreported Supreme Court case, including:

  • An actual threat being made.
  • The threat being of death or serious injury to the defendant or their family.
  • The threat being of such gravity that a person of ordinary firmness of mind and will, and of the same sex and maturity as the defendant would have yielded to the threat in the same way they did.
  • That the defendant acted the way they did due to the threat which was still acting on their mind at the time of the criminal act.
  • For such a threat to be effective it must be continuing and be perceived to be continuing. Such a threat will therefore not be continuing and effective if the accused had a reasonable opportunity to render the threat ineffective.

The burden of proof for establishing duress rests on the defendant, but once this burden is satisfied then the prosecution must prove that the defendant acted voluntarily beyond any reasonable doubt. However, it should be noted that duress is a defence to all criminal offences except for murder and treason. But duress is also a complete defence, so once it is established by the defendant the court must acquit them of all charges.


Defendants who have committed a criminal offence may also raise the defence of necessity, but only where they sincerely believed that they or their family would otherwise suffer immediate and irreparable harm. The defence of necessity shares some common elements with that of self-defence. In R v Loughnan (1981) the NSW Court of Criminal Appeal held that the required elements of the defence were:

  • The criminal act must have been done in order to avoid certain consequences which would have inflicted irreparable evil upon the defendant or upon others who they were bound to protect, and
  • The accused must honestly have believed on reasonable grounds that they were placed in a situation of imminent peril, and
  • The acts committed must not have been out of proportion to the imminent peril.

However, the necessity defence is solely limited to situations which overwhelmingly compel disobedience of the law, and thus it is usually difficult to satisfy the courts that the elements were present. Defendants applying have the evidentiary burden of establishing a defence of necessity, but once established the prosecutor must disprove the defence beyond reasonable doubt. Also, like duress, the defence of necessity is not available to defendants who have been charged with the crimes of murder or treason.


A defendant’s intoxicated state at the time of the alleged committal of a criminal offence may be taken into account by the courts, under certain circumstances. Under the Crimes Act 1900 (NSW), it is defined as meaning “intoxication because of the influence of alcohol, a drug or any other substance.” However, the criminal defence of intoxication is currently only available for the specific intent category of offences, which require proof from the prosecution that the defendant possessed a specific intent to bring about a specific result. Thus, intoxication may be used as a defence for a specific intent offence such as maliciously inflicting grievous bodily harm with intent to inflict grievous bodily harm. The intoxication defence is outlined in section 428C of the Crimes Act 1900 (NSW), which states that evidence of a defendant being intoxicated at the time of the offence may be taken into account in determining whether they had the intention to cause the specific result necessary for an offence of specific intent. However, such evidence cannot be considered by the courts, if the defendant had decided before becoming intoxicated to perform the relevant act, or they had become intoxicated to strengthen their resolve to perform the relevant act.

Claim of right

Another possible defence available to defendants, is where they committed a criminal offence because they had a sincere belief that they had a claim to a legal entitlement over property. There is no legal requirement for this sincere belief to be reasonable, but the reasonableness of the belief may be a relevant consideration for the courts when determining whether it was actually held. Once the defence is raised, the defendant has the burden of proving there was a genuine belief, and if this is proven the prosecution then has the burden of disproving it existed beyond all reasonable doubt. Section 9.5 of the schedule of the Criminal Code Act 1995 (Cth) sets out the requirements of the defence, stating that if at the time of the offence a defendant was under a mistaken belief that a proprietary or possessory right existed over property, they cannot be held criminally responsible for an offence that has a physical element relating to that property. The existence of any such proprietary or possessory right negates the fault element for any physical element of the offence. The section also states that a defendant is not criminally responsible for any other offence necessarily arising out of the exercise of the mistaken proprietary or possessory right. But it should be noted that this section does not negate criminal responsibility for any offence involving the use of force against a person. Also, the presence of fraud during the claiming of the legal entitlement would invalidate any claim of right, due to the lack of the requisite element of good faith.

Honest and Reasonable Mistake

Sections 9.1 to 9.4 of the schedule of the Criminal Code Act 1995 (Cth) sets out the requirements of the defence, stating that a defendant will not be held criminally responsible for an offence if they were under a mistaken belief about the facts at the time of committing the act.

The section also requires that this belief or ignorance of the facts negates the fault element, or that the belief was reasonable to hold in the circumstances. This defence may be present where the defendant had an honest belief in facts which if they had existed, would excuse their innocent act in contravention of the law. But the defence of honest and reasonable mistake is more limited in scope than other defences, because it is only applicable to strict liability offences, which are those that do not require the prosecution to prove that the defendant intended for the result to occur.

Consequently, this defence is most frequently raised in relation to traffic offences, such as Drink Driving (PCA) or speeding charges. It is also important to note that this ground of exculpation is only available where there is a mistake of facts, and not a mistake of law. An example of a mistake of fact is where there is a mistaken belief by the defendant that one of the elements of the offence was not present, when they were committing the act.

Once the defence of honest and reasonable mistake is raised, the defendant has the burden of proving there was an honest belief, and if this is proven the prosecution then has the burden of disproving it beyond all reasonable doubt.



Lawful Correction

In 2002 laws were introduced into NSW clarifying what constituted acceptable physical punishment of children by their parents. The requirements of the defence of lawful correction are stated in section 61AA(1) of the Crimes Act 1900 (Cth), where it states that the defence is available only where:

  • The force used on the child was for their punishment
  • The force was applied by the parent or a person acting for a parent of the child
  • With regard to the physical and mental characteristics of the child, or what the child did, the force that was used on the child was reasonable.

However, the force will not be considered reasonable under section 61AA(2) if:

  • The force was applied to the neck or head of the child, unless it was trivial or negligible
  • The force is likely to cause harm to a child that will last for more than a brief period

According to the legislation, a parent is defined as anyone having all of the duties, powers, responsibilities and authority over the child that a parent would have, such as a step-parent. If the defence of lawful correction is raised by a parent, the burden is placed on them to prove that they were correcting the child in their care, on the balance of probabilities. If you have any questions about what defence would be most appropriate to your current circumstances, or need any further information, please contact us.

Getting Help

Barclay Churchill Solicitors and Barristers
Level 11
111 Elizabeth Street
Sydney NSW 2000

Tel: 02 9635 3777
Fax: 02 9223 0276

Leave a Reply