David Garrett has resigned from Parliament, following the fallout from the revelation he stole the identity of a dead infant and used it to get a fake passport.

Mr Garrett resigned from Act last week after admitting he obtained the fake passport 26 years ago, and about the subsequent court case in 2005 where he was discharged without conviction.

He was granted name suppression in that case.

It was also revealed recently Mr Garrett was convicted of assault in Tonga while living there in 2002. He has been attempting to appeal the conviction.

Mr Garrett was Act's law and order spokesman, a strong campaigner for tough sentences and an opponent of name suppression.

After resigning from Act Mr Garrett has been on two weeks sick leave.

He tendered today his resignation, effective from midnight, a spokesman for Speaker Lockwood Smith said. Dr Smith has accepted his resignation.

In a statement Mr Garrett said his resignation was not forced but his own decision.

"As a result of my own foolish actions 26 years ago, I now have other battles to face."

He said he was grateful for the support he had been getting and regretted the damage his actions had caused the Act Party.

Act leader Rodney Hide said he was made aware of Mr Garrett's resignation via email and had not spoken to him.

The fact Mr Garrett had resigned did not mean he should never have been in Parliament, Mr Hide said.

"I wonder when we do things in our past, and appear before the courts, and pay the price that the judge decides, how long that should bar us from getting on with our lives."

It was difficult for MPs to decide what to declare, he said.

"I don't think there's a person in New Zealand, and I doubt there's any in our Parliament that haven't got things they've done in the past...that they're ashamed about or embarrassed about."

Mr Hide said he had been wracking his brain and could not think of anything he had not declared that would endanger his political career.

While the situation would impact on Act, Mr Hide said it showed the party had given Mr Garrett a second chance.

Mr Garrett had made all of New Zealand safer, he said.

"A lot of politicians have sat in this House and they haven't made anyone better off because they haven't done anything."

Act MP Heather Roy, who was recently ousted as deputy leader, said she had tried to call Mr Garrett but he was not answering.

In an interview with the Truth Weekly newspaper today, Mr Garrett said there were dark forces operating within Act. He indicated information about his passport scandal was leaked by a supporter of Mrs Roy and that he was collateral damage in a bid to smear Mr Hide.

Mr Garrett supported Mr Hide during Mrs Roy's leadership bid.

Mrs Roy denied being behind the leak.

"I knew very little of the information released last week. It wasn't me, it wasn't anyone associated with me."

As for the dark forces; "I think everybody might have been reading too much Star Wars myself," she said.

Prime Minister John Key said while Act had its own internal issues, he was confident of its ongoing support.

"They've earned the right to have five Members of Parliament...I'm absolutely convinced that those MPs will vote for a National government."

Dunedin lawyer heads for Parliament

Out goes lawyer David Garrett and in comes lawyer Hilary Calvert, as Act rearranges the deck chairs on its political Titanic.

Ms Calvert, 55, No 6 on the Act Party list at the 2008 election, is Wellington-bound after law and order hardliner Mr Garrett resigned from Parliament today after revelations he used a dead baby's identity to forge a passport.

Ms Calvert was a sole practice lawyer, specialising in property law, until recently. She lives in Dunedin with her husband of 30 years, Alastair Broad. They have three adult children.

She is landlord of several student flats - one of her tenants is a daughter of former Act deputy Heather Roy.

She has been on edge about coming to Wellington, since Mrs Roy was rolled as Act deputy in August and it seemed she might leave the party.

But Mrs Roy came straight back from her defeat, so Ms Calvert will instead take up the party slot abandoned by Mr Garrett - who had voted to remove Mrs Roy as deputy to Rodney Hide.

"I guess lawyers always find their way into Parliament partly because they care a lot about the structure of society and how it's run and partly because they understand the laws and things a bit differently," she told NZPA last month.

She left law to get into something more community focused and had been thinking about what to do, Ms Calvert said.

Parliament would be a good option - "that certainly counts as a serious community commitment".

Ms Calvert said Act could do with more support nationwide, that she was a regional person and would be out in the regions if she became an MP.

She studied law and philosophy at Otago University and was a former trustee for the Otago Rail Trail Trust.

Her training as a "couple counsellor" might be a handy tool in a fractured ACT caucus.

She feared ACT's message of less government, more personal choice and better use of taxpayer funds had been lost.