ACT is standing by its "three strikes" sentencing policy despite claims it would be ineffective.
The party's law and order election promises included a sentence of 25-years to life for anyone convicted three times of a violent offence.
Kim Workman of the Rethinking Crime and Punishment group says official information he has received shows the proposed legislation would not have stopped any of the prisoners currently serving life sentences.
But ACT MP David Garrett says the definition of violent crime was modified when the three strikes provision was incorporated in the Sentencing and Parole Reform Bill.
Mr Garrett says it adds the requirement that a person has been sentenced to a term of imprisonment of five years or more.
Department of Corrections figures show that none of the 423 prisoners currently serving life sentences had three qualifying sentences for serious violent offences prior to their most recent life sentence, as required under the proposed legislation.
Labour Party leader Phil Goff says ACT asserts that its legislation would have saved 77 lives, but the figures show no lives would have been saved.
Mr Goff has called on ACT leader Rodney Hide to publicly apologise.
