The Labour Party's plan to reform the criminal justice system would mean that the accused in a rape case would have to prove consent to be found innocent -- a change it acknowledges as a monumental shift.
But Labour's justice spokesman Andrew Little said the current system is broken and in need of a major shake-up. The party favours an inquisitorial system, where a judge interviewed the alleged victim after conferring with prosecution and defence lawyers.
The policy would mean that in a rape case, if the Crown proved a sexual encounter and the identity of the defendant, it would be rape unless the defendant could prove it was consensual.
"The Crown has to prove more than just sex; the issue of consent has to be raised by the Crown, they have to prove the identity of the offender. They would have to bear that burden of proof before a switch to the defence to prove consent," Mr Little said.
He said the issue of proof would only apply where allegations of rape had been raised.
"It is pretty radical thing to say that 'all sex is rape' unless you prove consent. The reality is that in 99.9 per cent of cases, no one is being asked to prove consent."
The Law Society has a strong stance on traditional principles of the legal system, including a presumption of innocence until proven guilty beyond reasonable doubt. It has argued strongly against inquisitorial systems in the past.
Mr Little said the inquisitorial system still preserved those principles because the Crown would still have to prove a number of aspects of a case before consent was explored.
"I don't accept that that is creating an offence under which the defendant is guilty until proven innocent."
He acknowledged the change would be a "huge leap".
"But when you look at the volume of sexual violence cases and the 1 per cent of cases that result in a conviction, there is something wrong with the way we are handling sexual violation cases. The circumstances may well justify doing something radically different."
In such a system, a victim would not be cross-examined by a defence lawyer.
"A defendant is entitled to have the evidence tested, but rather than face a defence counsel, which can be humiliating, a more controlled way is for the judge to conduct the examination, with counsel conferring with the judge beforehand," Mr Little said.
"That way a complainant can be assured the judge isn't there to do the best for one side or the other, but is there to get the information."
He clarified that Labour favoured the system, but its official policy is to have the Law Commission complete its report into inquisitorial systems, and then respond to that report.
Former Justice Minister Simon Power was a supporter of inquisitorial systems and asked the Law Commission to investigate. But his successor, Judith Collins, has called the system is "a step too far" and stopped the commission's work.