National Party MP Hamish Walker has admitted to leaking Covid-19 patient details.

Acting chief executive of Auckland Rescue Helicopter Trust Michelle Boag has confirmed she gave the patient details to Walker.

In a statement, Walker said: "I passed to members of the media, by email, information containing Covid-19 patient details that was given to me by a source."

Walker said he did this to expose the government's shortcomings so they would be rectified.

"It was never intended that the personal details would be made public, and they have not been, either by me or the persons I forwarded them to.

"I have received legal advice that I have not committed any criminal offence."

Walker said he sincerely apologised for how he handled the information and to the individuals impacted and would be "fully cooperating with the Michael Heron QC inquiry".

Boag falls on sword

In a statement, Boag said that handing on the patient details to Walker was "a massive error of judgement on my part and I apologise to my colleagues at ARHT (Auckland Rescue Helicopter Trust) whom I have let down badly".

"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.

She said she had resigned from her role at the Auckland Rescue Helicopter Trust.

"I take full responsibility for my actions and have resigned as acting CEO of ARHT."

Boag was the National Party's president in 2001 and 2002.

Stripped of portfolios

National Party leader Todd Muller has also released a statement saying Walker had informed him of his actions.

"I have expressed to Hamish my view that forwarding on this information was an error of judgement," Muller said.

"While I wait for the result of the inquiry I have transferred his Forestry, Land Information and Associate Tourism portfolio responsibilities to Ian McKelvie.

"Given this matter is the subject of an inquiry I will not be making any further public comment."