National's Clutha-Southland MP Hamish Walker is under intense pressure to resign as a candidate for the National Party after his outing this evening as the source of leaked covid-19 patient records to the news media.

Former National Party president Michelle Boag, an Auckland-based public relations industry consultant who has long had a high profile for her involvement in controversial and political activity, also disclosed that she had leaked the information to Walker, who then sent it to various media outlets.

"It's the only time I've done it," Boag told BusinessDesk.

With the general election only 10 weeks away, National Party leader Todd Muller stopped short of sacking Walker as an MP, but stripped him of his forestry, land information and associate tourism portfolio responsibilities while an inquiry ordered by State Services Minister Chris Hipkins is undertaken.

The inquiry, by Michael Heron QC, is expected to deliver its findings before the end of the month.

Walker, pictured bungy-jumping in Queenstown, had already attracted headlines in recent days. He issued a press statement that was interpreted as racist because he opposed the covid-19 quarantining of New Zealanders returning from Asia in hotels in Queenstown when they returned to the country.

Soundings among National Party sources tonight suggest there will be intense pressure on Walker either to resign from Parliament immediately or to withdraw his candidacy.

"Nothing is ever too late," said one MP on condition of anonymity, when asked whether it was too late for Walker, 35, to be deselected and replaced to stand in an electorate that has seen its fair share of controversy since the seat was vacated by former Prime Minister Bill English, who moved from the electorate and onto the party list in 2014.

He was replaced by Todd Barclay who was 27 when he announced in June 2017 that he would not stand for re-election after controversy involving allegations that he had taped electorate staff with whom he was in dispute and whose subsequent departure was paid for from the party leader's budget.

On his Kiwiblog site, National's pollster David Farrar said both Walker and Boag had displayed "staggering bad judgement".

"Under no circumstances should Michelle have sent that spreadsheet to Hamish, and under no circumstances should he have sent it to the media. It has private health information in it, being the names of people with covid-19," said Farrar. 

Walker issued a statement apologising, claiming to have received legal advice that he had not committed a crime by releasing the information, and that he had only wanted to expose the fact that the data on covid-19 patients "was not stored on a secure system where authorised people needed to log on."

Among the issues understood to be being considered by the National Party leadership and advisers is whether there has been a breach of the Crimes Act by either Walker or Boag.

In a statement, Walker said he would cooperate with the inquiry and apologised for his actions.

Boag's statement said: "The information was made available to me in my position as then acting CEO of the Auckland Rescue Helicopter Trust, although it was sent to my private email address.

"This was a massive error of judgement on my part and I apologise to my colleagues at ARHT whom I have let down badly."

She had resigned her position at the trust.

"I very much regret my actions and did not anticipate that Hamish would choose to send it on to some media outlets, but I am grateful that the media involved have chosen not to publish the 18 names that were contained within it."

Asked by BusinessDesk whether Walker's position as MP should be safe, she said "yes" and declined to discuss the matter further. 

Parliamentary records show Boag and Walker have had dealings in the promotion of legislation on behalf of at least one client of Boag's.

In August last year, NZ First MP Tracey Martin accused Walker in Parliament of sponsoring a private members' bill promoted by Boag to enable foster parents and guardians to enrol children in their care in KiwiSaver schemes - a bill that NZ First supported.

Boag gained notoriety when she organised the unauthorised videotaping of parts of the 'winebox' inquiry into tax avoidance when working for Fay, Richwhite, the merchant bank at the centre of the inquiry.

That incident led to questions about her suitability for the presidency of the National Party, which she won in 2001, going on to work with then leader Bill English to what was a historic defeat.

She was involved also in the so-called Saudi sheep deal, a project that saw a New Zealand-style sheep farm established in the Saudi Arabian desert as part of an effort by then Foreign Minister and long-time Boag confidant Murray McCully to seal a trade deal in the Middle East.

Boag remains an executive adviser to the New Zealand Middle East Business Council. She told BusinessDesk she wouldn't be resigning any other roles.