Fundamental pillars of the criminal justice system may be eroded whichever party wins the election this year, as both National's and Labour's proposals would look into changing the right to silence or the presumption of innocence in rape cases.
Both major parties claim the current system is not upholding justice for victims, and are looking at changes that would effectively make it easier for prosecutors to obtain convictions.
National wants to explore allowing a judge or jury to see an accused's refusal to give evidence in a negative light, while Labour wants to shift the burden of proof of consent from the alleged victim to the accused.
Auckland University law professor Warren Brookbanks said both policies challenged two fundamental principles: the right to silence, and the presumption of innocence, which are both protected in the Bill of Rights Act.
Of National's plan, he said: "It's an intrusion into the right to silence. In the trial process, offenders are in any event always at a serious disadvantage relative to the prosecution, and there are some important protections in the trial process, and the right to silence is a fundamental right. These are part of our democratic rights that apply to all citizens."