NZ Greens co-leader reveals cancer diagnosis

"Just over a month ago I was sitting in a doctor's office in one of those appointments you always hope you will never need," she said, surrounded by her caucus.

"A routine mammogram showed some potential concerns.

"Fortunately the cancer has been caught early ... early enough to give us the best odds of getting rid of it ... and treatment will begin soon."

Ms Davidson, leader since 2018, says she intends to hold onto the leadership role despite an estimated absence of four months.

Fellow co-leader Chloe Swarbrick, promoted to the role earlier this year, will lead the party during that break.

The Greens are New Zealand's third-biggest party, drawing a record 11.6 per cent support at last year's election.

However, the partyroom has been engulfed in scandal and trauma over the past 12 months affecting several MPs.

Elizabeth Kerekere left the party after bullying accusations, Golriz Ghahraman resigned from parliament after shoplifting charges and Darleen Tana remains in an investigation over questions of worker mistreatment by her family business.

Co-leader James Shaw announced his departure after the Greens fell from government at the 2023 election, while senior MP Julie Anne Genter is set for sanction for screaming in the face of a minister in parliament. 

Most significantly of all, Efeso Collins, a first-term MP tipped for leadership, died participating in a charity running event.

Ms Davidson said she believed her partyroom would be able to band together in her absence, and that Kiwis would use her diagnosis as a prompt to get checked.

"Please book in your mammograms," she said.