Immigration officials believed Chinese millionaire Yong Ming Yan married a woman in a deal over an Australian passport, papers reveal.

Documents also disclose his sister went missing in China, and he felt Chinese authorities had "turned" on him, owed him about $15 million and would kill him to obtain details of about 30,000 "secret members" of the Chinese Democracy Party.

A wealthy political donor, Yan - also known as Bill Liu - is at the centre of a political scandal after the former Labour government granted him citizenship in 2008, despite his being red-flagged by Interpol as a fugitive. He was wanted for fraud and identity theft in China.

Labour MP Shane Jones, who said he gave Yan a passport on humanitarian grounds, was stood down in May while the auditor-general investigated that decision. Yan was cleared of passport fraud by the high court.

Documents released under the Official Information Act included a file prepared by Immigration officials for minister David Cunliffe in 2007, in which they wanted Cunliffe to revoke the residency Yan was granted in 2002.

Officials had interviewed Yan in September 2005, and their transcript reveals he failed to declare his 2001 marriage in Sydney. He told them he lived with the woman for "half a year". Officials noted it was "possibly just a business deal for an Australian visa".

His wife moved to the US to study business.

Australian officials received an anonymous fax in 2002 stating the marriage "was not real", the papers showed. They later froze his bank accounts, repatriated $4m to China and declined his application for citizenship.

During the 2005 interview Yan told officials his only surviving relative - a sister - had gone missing after she travelled to China. He said he was born Yong Min Yang on October 20, 1971.

"I feel the government would put me in jail and kill me - and take my assets," he told them.

Yan's lawyers later prepared a lengthy submission pleading his case. It said he was born Yong Ming Yan on June 15, 1969, and his birth registered as October 20, 1972.

In 1999 he went to Chinese authorities for help after receiving death threats - and they gave him a second passport "as a means of protecting him", his lawyers said.

As "vice-chairperson" of the Chinese Democracy Party, which has 30,000 secret members in China, he was at risk of "illegal and unacceptable means to gain . . . information". Revoking his visa would put him and other party members "in mortal danger", lawyers said.

The letter detailed how he was owed money after a share deal with authorities went sour.

Immigration received another submission from a different lawyer on behalf of Yan in November 2006, which provided details of his business interests in New Zealand and his family situation. He was then in a stable de-facto relationship with a New Zealand citizen.

Cunliffe eventually recommended further investigation. In April 2008, Immigration obtained a search warrant for documents. Five months later, Yan was granted citizenship against the recommendation of Internal Affairs officials.

He did not respond to a request to his lawyer for comment yesterday.

- © Fairfax NZ News