Northland's Ngati Hine people are back in court seeking a ruling that the Ngaphui runanga cannot represent them in settling Treaty claims.
Ngati Hine is the largest sub-tribe in Ngapuhi and it has been trying to withdraw from the runanga and set up its own mandated iwi organisation to handle its share of fisheries assets.
It argues that the runanga committee, tuhoronuku, should not be able to claim it has a mandate to represent Ngati Hine in Treaty settlements, when Ngati Hine is trying to leave its parent body.
The Maori Land Court dismissed the case last October saying its jurisdiction did not extend to Treaty settlement issues.
But the Ngati Hine runanga has appealed against that decision, and will put its case on Tuesday to three judges at a hearing by the Maori Appellate Court in Whangarei.
The mandate question has divided Ngapuhi and discussions are continuing between the latest Government-appointed mediator Tukoroirangi Morgan and the opposing factions.