Disgraced Act MP David Garrett has quit his party and conceded his political career is almost certainly over.

However, Mr Garrett said in an interview with Radio New Zealand that was not his greatest concern.

"The worst aspect of all of this is that those who have seen fit to do so have opened the wounds of the boy's mother and sister again.

"As the person who inflicted those wounds in the first place, however unwittingly I must take ultimate responsibility for that."

He later released a statement in which he he said he regretted his actions.

"I can do nothing to change the past. For any number of reasons, I wish I had not done such a stupid and dreadfully hurtful thing in 1984. When my wrongdoing was revealed, the worst aspect of it all for me was reading the letters written by the mother and sister of the dead boy whose identity I used to obtain the passport.

"I wrote letters of apology at the time - letters I realised were woefully inadequate, but there was nothing else I could do. I wish to reiterate my profound regret for the distress and hurt my thoughtless actions inflicted on two women, one of whom is elderly. I am simply unable to imagine how it must have felt at the time they first learned of what I had done, and I am equally unable to imagine what they must feel now.

"I still well recall my horror when I read the letters from the boy's relatives, one of them in the handwriting of a clearly elderly lady. I do not think I have ever felt worse. There is certainly no excuse for what I did, and I make none."

Mr Garrett had not decided whether he would resign from Parliament or stay on as an independent, he told Radio NZ.

He would take two weeks' leave, consult with family and friends and make a decision after that.

However he said: "My political career is almost certainly over".

Hide returns to NZ

Act Leader Rodney Hide earlier refused to say what action he would take over David Garrett.

Mr Hide arrived back in Auckland about 8.30am after cutting short a trip to Hong Kong. He was greeted by about a dozen journalists at Auckland International Airport.

Mr Hide refused to answer questions on whether he would accept any offer of resignation from Mr Garrett and said he would speak to media after he had met with the MP.

"I will be speaking to him first," Mr Hide said. "I need to see David and talk to him."

Asked if he thought Mr Garrett's actions would impact on Act's election chances, Mr Hide said: "I'm not a person given to worry. I do my best to be the best MP I can for Epsom."

Mr Hide said his responsibility was to be a good minister.

Earlier this week, Mr Hide said he had "absolute confidence" in Mr Garrett.

Court documents

Details of Mr Garrett's deception are revealed in court papers from 2005 when he was charged with forging a document, namely a passport application form.

In his sentencing notes, Judge Keith de Ridder said: "There were deliberate acts involving several steps. There is a considerable act of planning in carrying out the crime."

The mother of the 2 year-old boy whose identity was stolen by Mr Garrett has described the identity theft as "stealing from the grave".

A brother of the dead child said yesterday that Mr Garrett was the "lowest of the low" and should be kicked out of Parliament.

Court documents reveal Mr Garrett visited a cemetery in New Plymouth in 1984 and found the gravestone of the boy, whose birthdate was close to his own.

He copied the details, obtained the child's birth certificate, filled out a passport application form and photographed himself in a disguise which included dyed hair and glasses.

Mr Garrett gave a fake postal address in Christchurch on his application form.

He was arrested 21 years later, after having first denied the allegations to police, and was discharged without conviction when the case went to court.

North Shore District Court Judge Philippa Cunningham yesterday revoked a suppression order placed on the case in 2005, but suppressed the identity of the baby and his family.

Judge de Ridder said in 2005: "Basically he has otherwise a blameless record and he seeks an order from the court to allow him to retain his reputation that he has built up over 13 years."

But the MP revealed on Wednesday that his record was not blameless, confirming that he had been charged with assault in Tonga in 2002 and fined $10.

One News reported last night that Mr Garrett might have misled the court by claiming in a document associated with his 2005 case that he had no criminal record.

- Paul Harper, Edward Gay, Jarrod Booker, Adam Bennett and James Ihaka and NZHERALD STAFF, ADDITIONAL REPORTING: NZPA