ACT New Zealand party MP David Garrett told parliament on Wednesday he thought at the time it was a "harmless prank" to get a passport by using a false identity - an idea he picked up from the bestselling novel Day of the Jackal.
The law and order spokesman said he never used the passport and eventually destroyed it, but 21 years later he was arrested during a police investigation into passport scams, appeared in court, pleaded guilty and was discharged without conviction.
On Monday Garrett, a first-term MP, confirmed he was charged with assault in Tonga in 2002 and fined $10.
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He said he was the innocent victim of an attack and had been trying to appeal the conviction ever since.
Garrett is a tough campaigner for stronger sentences and got the "three strikes and you're out" legislation through parliament.
In the debating chamber on Wednesday, opposition MPs heckled him with shouts of "strike two" and Speaker Lockwood Smith had to restore order.
Garrett made his statement to parliament after being questioned by reporters about whether he had ever been charged with offences other than the assault in Tonga.
He said he hadn't said anything about the passport because the court gave him permanent name suppression.
Labour leader Phil Goff said he felt for the family of the dead child - the child's sister told The Dominion Post family members were upset and distressed.
"The very worst thing here is for the family of that dead child whose identity was stolen," Goff told Radio New Zealand.
"They have effectively been gagged for years by a suppression order while they have to listen to Mr Garrett pontificating about being opposed to suppression orders, being in favour of openness, being in favour of the rights of victims and he's been anything but."
Goff said ACT had shown rank hypocrisy and it wastime for National to stand a credible candidate against ACT leader Rodney Hide in Epsom.
"How can you be a party of zero tolerance for crime.... how can you talk about three strikes when Mr Garrett has had his three strikes; firstly sexual harassment, then conviction for assault and now conviction for theft of identity."
Former ACT MP Deborah Coddington told the broadcaster the situation was farcical and the party appeared to be deeply divided and the ongoing sideshow was not good for the government either.
Deputy Prime Minister Bill English said the problem was ACT's to deal with.
"It's not a matter for the National party to determine who represents the ACT party," he told reporters.
"It's good to see an MP fronting up and explaining to the house what their situation is, but how it is dealt with is fundamentally a matter for the ACT party."
