Self-Defence Law in Australia: When is it Legal to Use Force?

Key Takeaways

• A Complete Legal Defence: Self-defence is not just an excuse; it is a complete legal defence in Australia. If successfully raised, it results in a verdict of "not guilty."

• The Two-Part Test: In states like NSW, the law asks two key questions: 1) Did you genuinely believe your actions were necessary? (Subjective test) and 2) Was your response a reasonable one in the circumstances as you perceived them? (Objective test).

• "Reasonable Force" is Key: You are only permitted to use force that is reasonable and proportionate to the threat you are facing. Using excessive force can negate your defence.

• You Can Act First: Australian law does not require you to wait to be hit first. If you genuinely believe an attack is imminent, you can act pre-emptively to defend yourself.

Introduction

It's a question many of us have considered in a fleeting, anxious moment: if you are attacked or threatened, how far can you legally go to protect yourself or your family? The law on self-defence is one of the most critical and most misunderstood areas of criminal law. It navigates the difficult line between a person's fundamental right to safety and the need to prevent unnecessary violence.

Popular culture often presents a distorted view, leaving people unsure of their rights. Can you defend your home? Do you have to wait to be struck first? What is "reasonable force"?

This guide will demystify the law of self-defence in Australia, explaining the legal tests that apply and the factors a court will consider.

Important Note: The laws of self-defence are governed by the legislation of each state and territory. This article will use the law in New South Wales (NSW), specifically Section 418 of the Crimes Act 1900, as a guiding example. The core principles are similar across Australia, but specific details can vary.

Learn more about Section 418 of the Crimes Act 1900 at New South Wales Legislation.

In NSW, self-defence is a complete legal defence to a charge involving the use of force, such as assault or, in the most serious cases, murder. This means that if the defence is successfully raised, the accused person is found not guilty of the offence.

The law recognises that a person is entitled to use force to:

• Defend themselves or another person.

• Prevent or terminate the unlawful deprivation of their liberty.

• Protect property from being taken, destroyed, or damaged.

• Prevent criminal trespass to their land or property.

To determine if an act was lawful self-defence, the court applies a two-part test. The prosecution must prove beyond a reasonable doubt that the accused's actions failed at least one of these parts.

Part 1: The Subjective Test – Did You Believe It Was Necessary?

The first question is about your genuine state of mind at the moment you used force. The court asks: Did you honestly believe that your actions were necessary to respond to the threat?

• This is a "subjective" test, meaning it is based on your personal belief at the time.

• Your belief does not have to be correct, but it must be genuinely held. For example, if you mistakenly believed someone was pulling out a knife and you acted to defend yourself, the court will consider your genuine, albeit mistaken, belief.

Part 2: The Objective Test – Was Your Response Reasonable?

If the court accepts that you genuinely believed your actions were necessary, it then moves to the second part. The court asks: Was the force you used a "reasonable response" in the circumstances as you perceived them?

• This is an "objective" test, but with a subjective element. The jury or judge must put themselves in your shoes and consider the situation from your perspective at that moment.

• Factors the court will consider include:

• The nature of the threat (e.g., its seriousness and imminence).

• The age, size, and gender of the parties involved.

• Whether any weapons were present.

• The options available to you at the time (e.g., could you have safely retreated?).

What happens if you genuinely believed you needed to act, but the force you used was unreasonable or excessive?

This is where the law becomes complex. Under NSW law, if you are on trial for murder and the jury finds that you used excessive force in self-defence (i.e., you pass the first test but fail the second), you cannot be found guilty of murder. However, you will instead be found guilty of the lesser, but still very serious, offence of manslaughter.

For a non-fatal assault charge, using excessive force would simply mean that your self-defence claim fails, and you would likely be found guilty of the assault.

Defending Your Home and Property

The law allows you to use reasonable force to protect your property or prevent trespass. However, the level of force considered "reasonable" to protect property is significantly lower than what is acceptable to protect a human life. Using deadly force to stop someone from stealing your television would not be considered a reasonable response.

Pre-emptive Strikes

A common myth is that you must wait to be hit before you can defend yourself. This is incorrect. The law allows for a pre-emptive strike. If you have a genuine and reasonable belief that an attack from another person is imminent, you are entitled to strike first to defend yourself.

Self-defence is a fundamental right recognised by Australian law, allowing you to protect yourself, your loved ones, and your property from harm. However, it is not an unlimited right. It is governed by a strict legal test of necessity and reasonableness.

Every act of self-defence will be scrutinised based on the specific, and often chaotic, circumstances in which it occurred. The law does not give you a license to use excessive violence, but it does provide a complete defence if your actions were a genuine and reasonable response to a genuine threat.

AHL Legal: Your Partner in Self-Defence Cases

Facing a self-defence case or need guidance on self-defence laws in Australia? At AHL Legal, we provide expert legal advice and representation to protect your rights and achieve the best possible outcome.