Labour is going into the next election with a justice reform platform aimed at boosting confidence that innocent people are not being sent to prison.
The party is developing a policy which would see new rules affecting everyone from the police officer to the Governor-General.
It comes as a new book into the murders of Harvey and Jeannette Crewe - The Case of the Missing Bloodstain - also calls for justice reforms.
Farmer Arthur Allan Thomas was twice convicted and then pardoned of murdering the couple in a case which featured claims of police planting evidence.
Author Keith Hunter said the Crewe murder case destroyed the public's trust in the justice system. He said subsequent cases around which there were questions, including the murder convictions of David Tamihere and Mark Lundy, had further eroded the public trust.
Labour justice spokesman Charles Chauvel said the party wanted to increase trust in the system through greater transparency and oversight.
He said the final recourse for those who believed they were wrongly convicted was to apply to the governor-general for the Royal Prerogative of Mercy, which allows for new trials or for convictions to be overturned.
He said the process, which was operated through the Minister of Justice's office, needed to be removed from any connection with political office. "It's not a transparent process. There is a need for something more than we have now."
Mr Chauvel said the discussion inside Labour was whether New Zealand needed an official body to oversee inquiries into miscarriages of justice or if it could be managed through independent people. He was unsure if New Zealand needed a fulltime commission.
He said there would also be a review of the Independent Police Conduct Authority which would ensure investigations were carried out impartially and for good reason.
Mr Chauvel said there should be an appointment to ensure cases were approached in the same way across the country.
Justice Minister Judith Collins said there was no need for a review because New Zealand had one of the best performing justice systems in the world.
Her office cited figures from Transparency International showing New Zealand as the least corrupt country in the world.By David Fisher @DFisherJourno Email David