A report by a senior Canadian judge on David Bain's claim for compensation for wrongful conviction and imprisonment contained assumptions based on incorrect facts and a misunderstanding of New Zealand law, Justice Minister Judith Collins says.
Ms Collins said she was concerned by some aspects of Justice Ian Binnie's report and after advice from the Solicitor-General decided it should be reviewed.
Ms Collins said she made it clear to Justice Binnie in September that there were concerns with his report and it would be peer reviewed.
She said the report contained assumptions based on incorrect facts, showed a misunderstanding of New Zealand law and lacked a robustness of reasoning used to justify its conclusions.
She said the decision had not been made lightly and she was disappointed a peer review was needed, but was "absolutely necessary".
"Put simply, it would not be acceptable to make a recommendation to Cabinet based on a report that would not withstand the considerable scrutiny it would attract.
"I think we would all agree that a timely conclusion to this matter would be best for everyone. But justice must be done - a robust and proper process is the only way to ensure a certain and final conclusion to Mr Bain's claim."
The reviewed report would be received this week and forwarded to Justice Binnie for comment.
"When I hear back from Justice Binnie, I will take a recommendation to Cabinet on the next steps," said Ms Collins.
In September, the Herald revealed that Justice Binnie had delivered a confidential report to the Government concluding that on the balance of probabilities, Mr Bain was innocent of the 1994 murder of his parents, brother and two sisters and should be compensated for time in jail.
Former All Black Joe Karam campaigned for Mr Bain, including taking a case to the Privy Council, which quashed his convictions in 2007 and ordered a retrial. Mr Bain was acquitted after a retrial in 2009.
The Cabinet has no obligation to follow the compensation recommendation. But if it does, the payout could be at least $2m, based on previous cases.
Talking to reporters on her way to caucus this morning, Ms Collins appeared annoyed that Justice Binnie had sent her two further unsolicited reports and said he would not be paid extra for them.
"Let me be very clear that I do not expect unsolicited reports which I have received two of in the last two months to be compensated for."
She did not want to go into details about Justice Binnie's reports and said Robert Fisher QC's review of Justice Binnie's findings would help Cabinet to determine in the New Year what the next steps would be.
"I am very concerned that there has been this delay. It would not have been possible for me to have put forward a recommendation based on a report that I believe would not stand up to public scrutiny."
She said that following Cabinet's final decision she would release as much as possible of the reports received.
"I know the public has a huge interest in this matter. As much as I can without defaming people or breaching legal privilege I expect to be able to release everything I can."
She said it was wrong to suggest that getting Mr Fisher to peer review Mr Binnie's report was "shopping around" for an opinion she liked.
"This is a peer review of Mr Binnie's report which is around the process, about some of the reasoning in the report, those sorts of things. It is not a report into whether or not Mr Bain is innocent or not on the balance of probabilities. Not is it a report as to whether or not there are extraordinary circumstances that Cabinet can take into account."
She was not concerned about how much the process was costing.
"It is not something I put a dollar value on when it comes to justice. I think justice is far more important than the dollar value.
"We don't ask our court to make quick decisions just because it is cheaper."
They were expected to make the best decisions they could.
She said justice officials told her that Bain supporters, at the time of the appointment of someone to look at the matter, had wanted an overseas judge to consider the claim.