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Possible defences to assault charges


What do I have to show in order to claim self-defence?

Crimes Act 1961, s 48

You’ll have a good defence to an assault charge if you were defending yourself or someone else. However, the amount of force you use has to be reasonable, given what you believed the situation to be.

Case: [2010] NZCA 44

So even if you were mistaken about the situation – for example, about whether the other person was going to attack you – you may still be able to claim self-defence. What’s important is whether it was an honest belief, not whether your belief was objectively correct.

But if your belief was mistaken, the force you used must still be reasonable when measured against your mistaken view of the situation.

Cases: (1989) 4 CRNZ 674 (CA); (2003) 20 CRNZ 319 (CA)

You don’t have to be reacting to an attack that’s already taken place – you can use force to prevent an attack that has been threatened and you believe is about to happen. In other words, you can use pre-emptive force.

Just because you’re angry or wanting revenge at the time, this doesn’t necessarily mean you aren’t acting out of fear of a potential assault, and therefore you may still be able to claim self-defence.

What does “reasonable” force mean when arguing self-defence?

Case: (1989) 4 CRNZ 674

What is reasonable depends on how immediate and how serious the force or threat against you was, and what chance you had to protect yourself without using force yourself – for example by backing away from the threat.

Cases: (2003) 20 CRNZ 319 (CA); [1971] AC 814 (PC)

But although the force you use has to be reasonable in the situation as you saw it, this doesn’t mean it has to be in reasonable balance with the force or threat as you saw it. For example, you may not have had a choice about the means of defending yourself, and you may have used a knife that was at hand against someone who didn’t have a weapon. The courts have said that if you did what you honestly and instinctively thought was necessary to defend yourself from an attack, that would be strong evidence that what you did was “reasonable”.

Do I have to prove I was acting in self-defence?

Case: [1975] 1 NZLR 760 (CA)

No. It’s not up to you to prove you were acting in self-defence. All you have to do is point to some evidence on which a self-defence claim could be based; once you do that, the prosecution then has to prove beyond a reasonable doubt that you weren’t acting in self-defence. If you don’t raise the issue, then the prosecution doesn’t have to address the question.

In other words, you just have to raise the question, based on some real evidence – it’s then the prosecution’s job to exclude the defence.

Defending your home or possessions

Using force to defend your home

Crimes Act 1961, s 56; Cases: [2014] NZHC 41; [2015] NZHC 1128

You’re justified in using reasonable force to prevent a person trespassing on your property, or to remove them.

However, you’re not allowed to hit or otherwise “strike” the other person, or cause them “bodily harm”. Pushing, shoving, fending off or obstructing the other person is allowed, so long as it’s proportionate and reasonable. Injuries to the other person like minor bruising will be acceptable, but any harm to them that’s more than “merely transitory and trifling” isn’t acceptable.

Crimes Act 1961, s 55

You’re also justified in using “necessary” force to prevent someone breaking into your home, if you believe on reasonable and probable grounds that the other person doesn’t have any legal justification for breaking in.

Using force to defend your possessions

Crimes Act 1961, s 53

You’re justified in using reasonable force to defend your possessions – this applies to any “movable thing”. “Movable” means what it says – it covers anything other than land and buildings, so it can include anything from your watch to your car.

Crimes Act 1961, s 53; Case: [2008] NZSC 3

This defence covers you if you do it under a “claim of right” – which means if you genuinely believe you have a legal right to the property. You can use this defence even if you’re mistaken about having a legal right to the property. It also doesn’t matter if it’s unreasonable for you to have this mistaken belief.

Case: (1984) 1 CRNZ 576 (HC)

To put up a “claim of right” defence, you only have to point to some evidence that raises this as a possible defence. It’s then the prosecution’s job to prove beyond a reasonable doubt that you didn’t have a genuine belief. It’s not your responsibility to prove that you had this belief.

Crimes Act 1961, s 53; Cases: [2015] NZHC 1128; [2014] NZHC 41

To use this defence, you’re not allowed to have hit or otherwise “struck” the other person, or caused them “bodily harm”. Pushing, shoving, fending off or obstructing the other person is allowed, so long as it’s proportionate and reasonable.

Next Section | Drug offences

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Common crimes

Where to go for more support

Community Law


Your local Community Law Centre can provide free initial legal advice and information.

Ministry of Justice


The Ministry of Justice website has a range of pamphlets and other information on the criminal court system. You can access this information online, or you can order hardcopies of the pamphlets from:

Phone: 0800 587 847
Email: publications@justice.govt.nz

Drug Foundation


The New Zealand Drug Foundation has a large amount of information about different drugs and their effects, and about criminal offences and penalties. They also provide drug checking services.



KnowYourStuffNZ provides free information, advice, and drug checking services using a range of testing methods at events around New Zealand.

The New Zealand Needle Exchange Programme


The Needle Exchange Programme provides and collects needles for safe disposal, advice on harm reduction, and is licensed to provide drug checking services.

The Level


The Level provides free guides for people who use drugs. Click on “I’m looking for drug checking” on their website for a calendar of non-festival drug checking clinics in Aotearoa.

Ministry of Health


The Ministry of Health has information about the legal use of cannabis products for medical reasons, and which particular products have been approved. Look under “Our work / Regulation / Medicines control / Prescribing cannabis-based products”.

Ministry of Primary Industries


The MPI website has information about recreational fishing rules and customary gathering rights.

The MPI also runs an automated information line that you can text to find out about minimum sizes and daily catch limits for particular species. Just text the name of the species in your message – just “paua” for example (it doesn’t work if you spell it “pāua”) – and send it to 9889.

How to find the cases we’ve cited in this chapter

This chapter cites a number of New Zealand court decisions as legal authority for the law as we’ve stated it. If you need to look up these cases, you can look at the references for each section and search for them either online or in a law library.

When we give the case citation, we give just the unique case reference – for example, “[2012] NZHC 15”. We haven’t included the case name (which is usually in a format like “Police v Douglas” or “R v Myers”).

You’ll be able to read most of these cases on the government website Judicial Decisions Online, at forms.justice.govt.nz/jdo/Search.jsp. The case will be on that site if the citation we’ve given includes either “NZHC” (for High Court), or “NZCA” (for Court of Appeal), or “NZSC” (for Supreme Court). You’ll need to search for the case on that site by inserting the citation (for example, “[2015] NZSC 135”) in the “Neutral Citation” search field.

Cases that have “NZLR” in the citation (for “New Zealand Law Reports”) usually won’t be available online, but they are available in hard copy in some larger city public libraries, published in orange-brown volumes. For the occasional case that we’ve cited from other report series (like CRNZ, for “Criminal Reports of New Zealand”), you’d need to go to a specialist law library at a university or local Law.

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