The in-limbo Ngāpuhi settlement entity, Tūhoronuku, is looking at removing Sonny Tau as a trustee for allegedly lying to them about his convictions.
Communications among board members, leaked to Newshub, reveal Tau's future is set to be discussed at the group's next meeting, which is expected to take place on September 23.
Concerns were raised internally when it became apparent that Tau may have lied about his convictions for possession of kereru, when asked to explain them to Tūhoronuku.
Trustee Moana Tuwhare, of Kaikohe Waimate Taiamai hapū, says Tau's actions raise "serious questions of credibility and honesty," and threaten the organisation's integrity.
"Over and above that… there's the issue of our core business being the Ngāpuhi negotiation and settlement, and obviously the Minister we need to negotiate with has got some firm views about Sonny Tau's position."
Ms Tuwhare believes Tau remaining on the board of Tūhoronuku is holding Ngāpuhi back from reaching a settlement with the Crown.
"It's not about any particular individual; it's about what's best for our Iwi."
Ms Tuwhare says Tau has had ample opportunities to be upfront with Tūhoronuku, but has chosen not to be.
She adds he has been a main cause of ongoing division amongst Ngāpuhi regarding settlement negotiations for eight years.
"One of the key personalities that has been part of… preventing us from resolving those issues, and coming together in unity, has been Sonny Tau," she says.
Te Tai Tokerau MP Kelvin Davis also believes Tau should step down from his leadership roles.
"We need to have total confidence in our leaders to be able to make the right decisions.
"The common sense thing to do would be to step down and allow someone else to come in and take over the role and lead Ngāpuhi into the future," says Mr Davis.
Treaty Negotiations Minister Chris Finlayson said on Wednesday that Tau should step down from tribal leadership roles, despite some in the tribe endorsing him to remain.
Sonny Tau was convicted last month of hunting and possessing kererū after five frozen specimens were found in his luggage at Invercargill airport on June 16 last year.
Tau initially admitted possessing the birds but said they were shot by his daughter's partner.
He later pleaded guilty to fabricating that story after Department of Conservation and Police enquiries.
Newshub could not reach Sonny Tau for comment.
Newshub.
