All five ACT MPs will vote for the Government's covert police surveillance bill.
Labour has also committed its support, after obtaining amendments that prevent the Video Camera Surveillance (Temporary Measures) Bill from applying to current police investigations or cases before the courts.
Last week, ACT MP Rodney Hide described the law change as something more suited to a banana republic.
But ACT parliamentary leader John Boscawen says all of its MPs will now back the bill, as it is no longer retrospective.
Prime Minister John Key says he's pleased there is enough support to pass the bill, but warns that because of the changes, some criminals may walk free.