A payout to an autistic man jailed for more than two years on a wrongful rape conviction should be increased to at least $1 million, top NZ lawyers say.

Aaron Farmer, 41, was found guilty of raping a 22-year-old woman in a Christchurch street in 2005 after a police detective lied while questioning him on the case.

He was sentenced to eight years in prison, but the Court of Appeal quashed his conviction in 2007. Shortly afterwards, new DNA tests excluded Mr Farmer as the attacker.

Associate Justice Minister Nathan Guy has apologised and issued Mr Farmer $351,575 in compensation.

Peter Williams QC, who helped free Arthur Allan Thomas, told Newstalk ZB the case was riddled with serious errors and shortcomings.

He called for Mr Farmer's compensation to be raised to at least $1 million.

"He's not only exonerated, he's exonerated beyond all reasonable doubt. He is completely innocent. He should be getting at least a million bucks."

Lawyer Stuart Grieve QC said the case showed the need to change the compensation system for people who are wrongfully convicted of crimes in New Zealand.

Rules set in place by Cabinet in 1998 put the starting annual rate for compensation at $100,000 - but that was adjusted upwards in Mr Farmer's case because of the serious impact of his conviction and imprisonment.

Mr Grieve said it was almost impossible to quantify the damage being in prison for more than two years had done to Mr Farmer.

"The damage is huge and when it starts to run into years. To quantify it in dollar terms, some people would say it's almost immeasurable.

"I think sticking with the system we've got - making it more generous is part of the answer."

Mr Williams called for an independent investigation into the case to look at the role of police forensic teams.

It was concerning a jury did not get to hear important alibi evidence that may have swung the verdict in the original 2005 trial, he said.

"I think there should be a full inquiry into how a completely innocent person was convicted by our judicial system and as a result this man spent at least two years in custody."

The Court of Appeal criticised a detective who handled the case for telling Mr Farmer police had DNA evidence linking him to the case when there was none.

The officer, who was widely criticised by the courts and his superiors, is no longer working as a detective, but is still working for the police in Wellington. He did not return calls yesterday.

Mr Farmer's trial lawyer Tim Fournier was also criticised for his handling of the case.

The Government is also considering whether to compensate two Manawatu men for their wrongful conviction and imprisonment over a 2003 arson.

Phillip Johnston and Jaden Knight had their sentences quashed on the grounds of misdirection by the judge. In 2007 they applied to the Justice Minister for compensation.

Austism NZ says justice has been served

Meanwhile spending two years in jail would have inflicted more pain on autistic man Aaron Farmer than someone without the condition, Austism New Zealand says.

It has applauded the Government $351,575 payout.

Chief executive Alison Molloy said that injustice would have been felt particularly strongly because of Mr Farmer's autism disorder.

"The payment in acknowledgement of that is a really good step in terms of increasing awareness about the impact on people with autism in these sorts of circumstances," she says.

Ms Molloy said the case also highlights the need for people with autism to get treatment.