A Kiwi war hero is being held at a high-security prison across the Tasman - despite not having a criminal record.

Former Lance Corporal Ngati Kanohi Te Eke Haapu, known as Ko Rutene, had his visa revoked on the grounds he was a member of a motorcycle club, Fairfax reported.

It is understood he is being held at the Casuarina maximum-security prison in Perth.

A law change in Australia means foreign-born nationals automatically have their visas revoked if they have convictions with penalties totalling more than 12 months in prison.

Rutene, 34, was taken into custody over a week ago, Fairfax reported.

Lawyer Michael Pena-Rees told Fairfax that Mr Rutene had "exceptional good character" and no criminal record in New Zealand or Australia.

Mr Rutene - a gunner in the New Zealand Army - had served from 2008 until 2012 and received three medals of honour during this time.

In 2010 he served in Afghanistan in a "Quick Reaction Force", rescuing units who were under attack.

He also helped to protect the unit and evacuate injured during a high-profile attack in Afghanistan where Kiwi soldier Lieutenant Timothy O'Donnell was killed.

Mr Pena-Rees said police used tasers on Mr Rutene, who moved to Australia three years ago and lived with his partner and her son.

He was forcibly detained and forced into solitary confinement for four days, because of his connection with the Rebels motorcycle gang, Mr Pena-Rees said.

"The Rebels OMC is not a criminal organisation in Western Australia," Mr Pena-Rees told Fairfax.

"To be a risk to national security because of his connection to an outlaw motorcycle club is an abhorrent and ill-conceived decision in light of the fact that Ko is a decorated ex-soldier, who, as part of the ANZAC spirit, served overseas for the same reasons as Australia and its soldiers."

Mr Rutene should be released immediately, he said.

Maori Party MP Marama Fox told Fairfax she brought up Mr Rutene's situation to Prime Minister John Key on Tuesday, after Mr Rutene's family had contacted her saying he had committed no crime.

Mr Key said he had no details of his case.

"He is barely a member of the Rebels motorcycle gang, he is a decorated serviceman and he is being held in a detention centre," said Fox.

"The Prime Minister's got it wrong and he needs to do more."