MP Hamish Walker has stepped down as the National Party's candidate for Southland after he admitted to leaking COVID-19 patient data to the media.
"Today I am announcing that I will not be standing for re-election for the Southland electorate at the upcoming 2020 election," Walker said in a statement on Wednesday.
"I wish to thank the people of Clutha-Southland who I have loved meeting, assisting and representing over the past two and a half years. I sincerely apologise for my actions."
National leader Todd Muller said shortly after that he had accepted Walker's decision to withdraw his candidacy for the seat of Southland.
He said Rachel Bird, the National Party's Southern Regional Chair, had received a letter from Walker confirming he will withdraw.
"There was a clear breach of trust, which goes against the values National holds as a party," Muller said. "The National Party Board will still meet today to discuss the selection of a new candidate."
The first-term MP, 35, admitted on Tuesday to leaking to the media information containing sensitive COVID-19 patient details he said was given to him by a "source".
Shortly after Walker's revelation, ex-National Party president Michelle Boag confessed to passing on the data to Walker - information she said was made available to her as acting CEO of the Auckland Rescue Helicopter Trust.
Boag has resigned from that role and stepped down from National Party deputy leader and Auckland Central MP Nikki Kaye's campaign committee.
Walker apologised on Tuesday for how he handled the information, but he said he passed on the information to the media to "expose the Government's shortcomings".
"The information that I received was not password protected by the Government. It was not stored on a secure system where authorised people needed to log on. There was no redaction to protect patient details, and no confidentiality statement on the document."
The National Party board met on Wednesday to discuss the fate of Walker after Muller wrote to the board asking to have the Clutha-Southland MP removed.
Walker was going to stand as National's MP for Southland. The Clutha-Southland electorate was renamed Southland in the latest electorate boundary changes.
Muller said in a statement on Tuesday that Walker had been stripped of his Forestry, Land Information and Associate Tourism portfolios, which have been handed to National MP Ian McKelvie.
Speaking to The AM Show on Wednesday, Muller said Walker's actions did not reflect the National Party's values and the MP had lost his confidence.
"His approach is completely unacceptable; not reflective of the National Party I want to lead."
Muller found out about Walker's involvement in the leaked data on Monday at which time the Government had announced an inquiry. Muller sought legal advice and said Walker needed to go public.
"Bluntly, that took just over 24 hours but it is what it is - that's how it happened but I was never going to move from the course that this needed to be made public and it was."
He described Boag's actions as "appalling".
Health Minister Chris Hipkins told reporters on Tuesday the leak had a "ring of dirty politics to it".
"I think if a Member of Parliament can't accept that receiving people's health information is something they should treat with a degree of confidence, then that says quite a lot about their own levels of personal integrity and judgement."
The controversy is Walker's second rebuke from Muller.
Earlier this month Muller expressed "disappointment" after the MP released a media statement warning thousands from "India, Pakistan and Korea" could be destined for managed isolation facilities in the south without consultation.
Prime Minister Jacinda Ardern said she found the MP's comments "inappropriate" while the minister in charge of managed isolation facilities, Megan Woods, described them as "racist".
Walker attempted to defend those comments by sending information showing the country of origin of the COVID-19 cases, according to RNZ, one of the media organisations send the sensitive patient data.
RNZ made a commitment to Walker before receiving the information, not to name him as the source. The media outlet reported it had received the information on Saturday July 4 but chose not to publish it.
Muller described the leak at the time as "shabby".
Hipkins on Monday appointed Michael Heron QC to lead an investigation into the leaked information. He said the investigation will continue despite Walker and Boag coming forward.