Key Points:

Act won a small but significant victory in Parliament last night, with Labour supporting a victims' rights amendment in the Criminal Justice Reform Bill rather than face the embarrassment of losing a vote.

Once Act had gained the support of NZ First MP Ron Mark for its amendment, Labour had to support it or lose the vote.

The bill, which amends the Sentencing and Parole Act, would have removed the automatic right of the victims of crime to attend parole hearings.

It talked of victims being "invited" to make submissions at hearings on the risk to the community of releasing the offender.

Act MP Heather Roy proposed an amendment removing the reference to being invited, in effect reinstating the right of victims to attend parole hearings without invitation and reinstating their right to talk about the actual crime, rather than the risk surrounding release.

Several Labour MPs spoke against the amendment before Justice Minister Mark Burton agreed to support it.

National law and order spokesman Simon Power said it was clear that the minister had been forced to change his mind in the House and "cut the legs out from under" two MPs who had spoken against the Roy amendment.

"That is one of the few times I have seen the Government changing its view on a matter out of select committee as the mood and the votes in the chamber turned."

The vote shows the potential difficulty the minority Labour Government has in passing legislation other than confidence and supply matters, which it can pass with ease with the Greens' abstention.

NZ First supports Labour on confidence and supply but everything else is on a case-by-case basis.

Adding to its difficulties in securing votes has been the defection of Taito Phillip Field from Labour and Gordon Copeland from United Future to become independent MPs.

Mr Copeland yesterday confirmed he was seeking the advice of the Clerk of the House, David McGee, over what constituted confidence and supply issues. His proxy vote for such issues lies with Labour but on all other issues it's with National.

He said he was concerned to ensure there was never a situation in which whips from both parties believed they were exercising a proxy vote for him.