UPDATED 11.08AM: Ngapuhi leader Sonny Tau has stepped down from his role leading Northland treaty settlement negotiations - but it's not known whether he jumped, or was pushed.

Tau was questioned by Department of Conservation officials, after he was found to have concealed several of the dead native wood pigeons (kereru) inside his coat as he was boarding a flight from Invercargill to Northland.

He admitted the allegations, saying it was a mistake which he regrets. He is currently being investigated. 

Tau is one of the lead negotiators on the Nga Puhi Treaty settlement. 

Treaty Negotiations Minister Chris Finlayson believes there are plenty of people in Ngapuhi who can step into the breach.

Finlayson doesn't think the resignation is permanent, but said that was for the iwi to resolve either way.

The negotiations between iwi and the Crown are at a sensitive stage and Prime Minister John Key said it was important for Northland that they're completed.

"One of the big things I think that can move Northland forward is the successful completion of that Treaty settlement, hundreds of millions of dollars involved," Key said.

Fellow Ngapuhi leaders have backed Tau's actions, saying eating kereru is a Maori customary right.