The three strikes law will be scrapped by this Government, it's only a matter of when.

The confirmation comes after a Wellington man with a mental health history was sentenced to seven years jail yesterday for trying to kiss a woman on the lips.

The judge however, waived the non parole requirement under the law which means he'll be eligible for release after serving just a third of his sentence.

Justice Minister Andrew Little says there'll be a criminal justice summit in July to discuss these sorts of issues.

"What this case shows is just the efforts judges are having to go to to come up with a decision that is actually defective for the defendant as well as keeping the public safe, as looking up someone who is mentally unwell is not going to fix the problem."

Little says a number of law changes will flow from it.

"It's not just three strikes law, there are a whole heap of laws that are happening that are seeing a rapid growth in the prison population [but] isn't seeing our serious violent offending rate going down. After thirty years of a discourse where people have been told unless we lock more people up, we're all going to be unsafe, we've got to turn that back."