Richard Worth has resigned as an MP with immediate effect.
Dr Worth, who entered Parliament in 1999, said he had gone for the good of the National Party.
"Since I resigned as a Cabinet Minister earlier this month, I have been considering my personal options, and also the welfare of the National Party - a party which I love and have served to the best of my ability for the past nine years.
"As a result, I have today also resigned as a list Member of Parliament with immediate effect.
"It would be easy for me to be bitter about the avalanche of rumour and innuendo that has led me into making this decision which I regard as being in the best interests of my party.
"I wish only to restate that I have not committed any crime, and I remain confident that when the true facts are established I will be cleared of any and all allegations of criminal conduct. I will steadfastly defend myself in respect of those allegations. But it is impossible to defend oneself in the public and political arena against hearsay, character assassination and scuttlebutt."
Dr Worth stepped down as a minister last week after he was confronted about claims of a sexual nature that are being investigated by police.
He has been under pressure to quit as an MP after Prime Minister John Key made it clear there was no way back as a minister, regardless of the outcome of the police inquiry.
Mr Key said yesterday he had "washed his hands" of Dr Worth, sending his clearest signal yet that he wanted him out of Parliament.
Dr Worth has also been accused of sexually harassing Labour Party activist Neelam Choudary with 100 phone calls and texts over 90 days during the summer.
Prime Minister John Key said Dr Worth's resignation was "a sensible course of action".
"The decision gives the country an opportunity to move forward and focus on the issues that matter."
In a statement, Dr Worth said he was "moving forward on a new path".
"Like most of us, if we are honest, I may at times during my life have said and done things which, when analysed in the cold light of day, may seem to have been unwise. As I said last week, like any other citizen I am entitled to the presumption of innocence until proven guilty.
"I could spend the future bemoaning the unfairness of a campaign which has Labour's fingerprints all over it. But that is not my nature. The campaign has been run against me by people who are unable or unwilling to back their claims with credible evidence of criminal activity.
"I went into politics to make a contribution to New Zealand. I can see that it is no longer possible for me to do that through politics, so I am now choosing to follow another positive path.
He said he would work in the area of international trade.
"I believe I may make a greater contribution through my business activities than by attempting to remain in politics in what would clearly be an untenable position, and hoping to be forgiven for things of which I am innocent.
"My conscience is clear. Those who have chosen to try to ruin my reputation should perhaps now examine theirs.
"My wife and family stand behind me in this decision, as they have stood by me, together with our friends, in the past difficult weeks. Their loyalty and love has been a timely reminder for me about what is truly important in life.
"This whole episode has taken a toll on me personally, and this is why I have made myself unavailable to the media and will continue to do so. I would ask that media now respect my right to privacy and allow me to get on with my life."
National list candidate Cam Calder will take Dr Worth's place in Parliament.
Labour leader Phil Goff said Dr Worth's resignation was expected following Mr Key's statements yesterday.
When a leader loses confidence in a list MP, "as John Key obviously had", there is no other choice but to resign, Mr Goff said.
Labour had nothing to do with the police investigation which was what had led to Dr Worth's dismissal as an minister, Mr Goff said.
Mr Goff went to Mr Key "privately" to raise the issue of Dr Worth's contact with Mrs Choudary because it was "clearly inappropriate" behaviour for a minister.
But that was a separate issue to the police investigation, Mr Goff said.
- © Fairfax NZ News
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