Justice Minister Andrew Little is hopeful that New Zealand First will support repealing the controversial "three strikes law".

Little told the Herald this evening that New Zealand First, Labour's government coalition partner, wanted to consider the proposal as part of a wider justice reform package, not on its own.

"They are nervous about repeal of three strikes but they're not saying never, ever. They've said to me 'we want a comprehensive package of reform, let's look at everything together as opposed to just these handful of bids'," Little said.

The New Zealand First caucus will meet tomorrow where MPs will discuss the party's position on repealing the law.

Advertisement

Little said publicly last week he had been intending to take a paper to Cabinet today on the repeal but announced this morning that he had ditched it because of a lack of support from New Zealand First.

Speaking to reporters earlier today, he refused to say whether he had not consulted his coalition colleagues properly in the first place or whether New Zealand First had changed its mind.

He said New Zealand First wanted to consider a reform package for the criminal justice system to be considered by an independent advisory panel which would be appointed shortly, and which would be progressed at a criminal justice summit in August.

Prime Minister Jacinda Ardern told reporters it was a "given" that ministers did not make announcements before discussing them at Cabinet.

"There's always a given that we wouldn't do that. It's something that doesn't really need requirement to be repeating. It's an absolute given," she said.

"Three strikes makes up only a very small part of a much wider agenda and we are continuing to pursue that agenda as a Government. None of these decisions are finalised until we have that discussion as Cabinet. All our ministers know that," Ardern said.

"It's always much tidier to wait until Cabinet but the minister has actually made the decision that he wants all of this work to be pursued as a whole anyway."

She said any perception that the coalition Government couldn't agree and couldn't get things done was wrong.

"That perception would be absolutely wrong ... we are a Government that is committed to moving away [from a] US-style justice system to making sure we have an effective system that keeps our communities safe and focuses on crime prevention and we're still committed to that."

New Zealand First leader Winston Peters issued a brief statement welcoming Little's decision not to proceed with his recommendation to Cabinet.

"The caucus looks forward to working with him on achieving a balanced reform package," Peters said.

Under the law, which was passed by the National-led government in 2010, a person with three warnings after serious violent, sexual or drugs convictions must be sentenced to the maximum jail time without parole unless the sentencing judge believed it would be manifestly unjust.

National leader Simon Bridges said Little's backtrack today showed incompetence from an amateur Government and had "underlined cracks in the coalition".

He said Little had been "hauled into line" and had clearly been making promises he had not done the work to keep.

The Sensible Sentencing Trust, which ran a full-page ad in the Herald today calling on Little to drop his plans, thanked New Zealand First for forcing the change.

Founder Garth McVicar said New Zealand First knew the public would not support a return to the days of "failed soft-on-crime policies that do not deliver justice and marginalise victims at the expense of the 'rights' of dangerous recidivist criminals".

McVicar said Little should also drop "his outrageous plans to weaken the bail law, increase the already over-used home detention" and that he should push forward to build more prison space.

The Government will announce its decision on the future of Waikeria Prison on Wednesday. It has already flagged a 'mega-prison' is off the table.

The open letter to Little published in today's Herald was signed by mostly relatives of people who have been killed or severely abused by offenders.