Act's flagship three-strikes policy is falling apart, with its format derided even by the hardliners of the crime debate.
Prime Minister John Key yesterday said the problems were of Act's own making, because it agreed to the five-year sentence threshold to earn a "strike" that has rendered it largely ineffective.
The Act MP who designed the policy, David Garrett, will not even commit to supporting the present version.
The problems are compounded now that Mr Garrett is caught up in a row over making inappropriate comments about a female staff member just as the three-strikes policy reaches its most critical point if it is to progress any further through Parliament.
Act campaigned on the three-strike policy and after the election agreed to it being merged with National's sentencing measures, with the change made that an offender had to be sentenced to five years or more to earn a strike.
That five-year threshold is so high that not even RSA triple-killer William Dwane Bell or samurai sword killer Antonie Ronnie Dixon would have been "struck out" before they committed their notorious murders.
Its impact would not be felt for another 10 years when just 25 more prison beds are expected to be needed.
This prompted the Sensible Sentencing Trust - which did a deal with Act to get its former legal adviser Mr Garrett into Parliament to push the policy - to turn against it publicly last week and say it now only purports to be tough. Mr Garrett told Q+A on Sunday he was unhappy about the policy as it stood and would not necessarily vote for it.
He would not return calls yesterday.
Mr Garrett and Act may not even get a chance to vote for it as National only agreed to support it to the select committee stage, which has just finished hearing submissions on the Sentencing and Parole Reform Bill it is part of.
National's caucus will decide whether to support three strikes continuing as a component in the bill's second reading.
It is unlikely National would agree to removing the five-year threshold as it would require dismantling its own hardline sentencing measures, which were a key election policy.
Prime Minister John Key said Act turned down the opportunity to have three strikes run as a separate bill, preferring instead for it to be "embedded" with National's measures.
He said National had honoured its governing agreement with Act for three strikes to go to a select committee, and if the threshold of five years was now causing problems, it was not National's fault.
"We haven't tried to undermine the process - we've simply followed what they [Act] asked us to do."
Labour MP Clayton Cosgrove said Mr Garrett's refusal to commit to three strikes was a slap in the face for the murder victims' families who had appeared before the law and order select committee to support it.
"Would those victims have shown up if they had known the author of the bill was not going to support it?"