The current law
3.1In New Zealand, any person charged with murder may, broadly speaking, defend the charge in one of three ways, which are to:
(a) contend they were acting in self-defence;
(b) contend they did not have the requisite murderous intent; or
(c) plead not guilty and put the prosecution to proof.
3.2Self-defence is a complete defence. If the jury accepts it, the defendant will be acquitted; the killing is not a culpable homicide. The alternative strategies in (b) and (c) will not necessarily result in an acquittal. The jury may find that the evidence proves culpable homicide but, because of lack of murderous intent, does not prove murder. In that case, the jury may find the defendant guilty of manslaughter. That may also be the case where self-defence is rejected by the jury. This is discussed further below.
3.3A person charged with manslaughter can also claim they acted in self-defence or, again, can simply put the prosecution to proof.