National MP Hamish Walker confessed to leaking private health information about active Covid-19 cases to the media.
National party leader Todd Muller has since requested Walker to cooperate with investigator Michael Heron QC over how this information was made public.
Muller said he had told Walker leaking the information to the media was an error of judgment.
He has transferred Walker's Forestry, Land Information and Associate Tourism portfolio responsibilities to Ian McKelvie.
Hamish Walker remains the MP for Clutha-Southland.
Walker replaced one-term MP Todd Barclay after a staff dispute in the electorate's Gore office. The previous MP was Sir Bill English.