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This article was written by Michelle Makela - Legal Practice Director

Michelle has over 15 years experience in the legal industry, working across commercial litigation, criminal law, family law and estate planning.  Michelle has been involved in all practice areas of the firm and in her personal practice has had experience in litigation at all levels (state and federal industrial tribunals, the Supreme Court, Court of Appeal, the Federal Court, Federal...

Partial Defences To Murder

Partial defences to murder can be used to reduce a verdict that would otherwise be murder to manslaughter. The accused will be convicted of manslaughter, even though all of the physical elements of murder are proved. This article outlines partial defences to murder in New South Wales.

Partial defence to murder: Provocation

Section 23 of the Crimes Act outlines the defence of provocation. The defence applies where there is conduct which could deprive an ordinary person of self-control and which, in fact, deprived the accused of self-control.

There is no requirement that the killing must follow the provocative conduct immediately. The loss of self-control can develop after a prolonged period of abuse, without the need for a specific ‘triggering’ incident.


The defence of provocation is made up of four key elements:

1. Provocative Conduct by the deceased directed at or affecting the accused.

There must be conduct that occurs in the sight or hearing of the accused to which the accused reacts. The provocative incident must directly involve the accused and deceased, although the conduct may not be directed intentionally or specifically against the accused.

2. Causation.

The provocative conduct must have caused the accused to lose control and kill the victim. When determining whether the accused lost self-control, the accused’s personal characteristics, including whether he or she was intoxicated, are considered. This is because the law appreciates that conduct which may not be provocative to one person may be provocative to another because of that person’s personal characteristics such as age, cultural background, physical features, relationships or past history.

3. An ordinary person in the accused’s position might have been provoked by such conduct.

The ordinary person is a person of the same age as the accused but does not have other personal characteristics, such as sexual preference, ethnic background, state of intoxication and physical disability.

4. An ordinary person in the accused’s position might have lost self-control to such an extent as to act as the accused did in resorting to the use of deadly force.


The accused has an ‘evidentiary burden’ such that he or she must provide some evidence that raises the possibility that he or she acted under provocation. The Crown must then prove beyond reasonable doubt that the accused was not acting under provocation.

Partial defence to murder: Substantial impairment by abnormality of mind

Section 23A of the Crimes Act outlines the defence of substantial impairment by abnormality of mind.


The accused must show on the balance of probabilities (that it was more probable than not) that:

1. At the time of the acts causing death, the accused’s capacity to understand events, or to judge whether their actions were right or wrong, or to control themselves, was substantially impaired by an abnormality of mind arising from an underlying condition.

“Abnormality of mind” refers to a state of mind so different from that of ordinary human beings that a reasonable person would deem it abnormal. However, the abnormality must arise from various specified causes. It must arise from a condition of arrested or retarded development of mind; may be induced by disease or injury; or may arise from an inherent cause (whether inherited or acquired from the environment provided it is not of a merely temporary nature). The court must disregard evidence of self-induced intoxication for the purposes of determining whether the accused was acting under an abnormality of mind.

Medical evidence as to whether the accused suffered from an abnormality of mind at the time of the offence is important when raising this defence. However, it is not always conclusive. The whole of the material may be considered, including the accused’s acts, statements, manner and demeanour. The jury is entitled to reject medical evidence if there is other material that, in the jury’s opinion, conflicts with the medical evidence and outweighs it.

2. The impairment was so substantial to justify reducing the accused’s liability for murder to manslaughter.


Section 22A of the Crimes Act governs the partial defence of infanticide. This defence applies where a woman willfully causes the death of her child within 12 months of birth but at the time of the act the balance of her mind was disturbed because she had not fully recovered from the effect of giving birth or by reason of the effect of lactation consequent upon the birth of the child.

If the defence of infanticide is successfully raised, the court will reduce a conviction of murder to a conviction of manslaughter.

If you require legal advice or representation in any legal matter, please contact Armstrong Legal.

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