National MP Hamish Walker has confessed to passing private details of Covid-19 patients to the media.
A privacy breach of active Covid cases was reported by the Weekend Herald, which the Government called serious and possibly criminal.
An inquiry has been launched, headed by Michael Heron QC.
Walker, who is MP for Clutha-Southland, says he passed the details to the media.
He was stripped of his Opposition portfolios by leader Todd Muller, who said that Walker had made an "error of judgment".
Speaking on The Huddle with Heather du Plessis-Allan, guests Josie Pagani and Shane Te Pou both criticised Walker's actions.
"Two strikes and he's out. He's probably broken the law, he's certainly breached people's privacy," Te Pou said.
"Not only is it a mess, but it's embarrassed the National Party when in fact they were setting out to embarrass the Government," Pagani added.
du Plessis-Allan says Todd Muller will be unable to criticise Jacinda Ardern for not firing her Ministers if he does not do the same himself.
"He cannot hold her to account if he allows Hamish Walker to continue."
In another twist, former National Party President Michelle Boag has confessed she passed the information to Walker through her role as the acting CEO of the Auckland Rescue Helicopter Trust.
On Saturday, before they knew Walker's involvement, Muller and National's health spokesman Michael Woodhouse were damning of the privacy breach.
"This is unconscionable and unacceptable that those suffering from the incredibly dangerous virus now have to suffer further with their private details being leaked," Woodhouse said.
"The Government needs to get to the bottom of this, and quickly."
Muller told RNZ the breach was "quite staggering" and "unacceptable".
"Is it a deliberate leak or is it accidental? It doesn't really matter at a level ... it's loose, it's shabby and it's a reminder these guys can't manage important things well."