Maori in Northland are challenging the regional council's role in the mining of swamp kauri.
The council's new Maori Advisory Committee grilled the council this week on why it allows wetlands to be dug up, and how it monitors the mining.
Some whanau in the Far North have been actively involved in swamp kauri mining, but many hapu are fiercely opposed to it.
Several members of the advisory committee told the council their elders had banned the milling of trees, and the mining of swamp kauri in the 1980's.
And frustration was evident over the regional council's role in enabling the export trade to continue.
The council's responsible for issuing resource consents if the mining involves the disturbance of wetlands, and monitoring any adverse effects.
Hokianga rangatira and scholar Patu Hohepa said no-one was addressing the primary question, of who owns the kauri.
"In terms of Te Tiriti, it still goes back to the original owners of the land," he said.
"Because they are taonga. And the second question is who has the right to have them harvested in the way they're doing?
"It is wrong under any kind of protocol," Dr Hohepa said.
"It demeans the mana of the kauri, but it also ruins the land."
The Resource Management Act says councils must preserve the natural character of wetlands, which it defines as permanently or intermittently wet areas that support natural ecosystems.
However, the Northland Regional Council has narrowed the definition of wetlands requiring protection.
Its Water and Soil Plan protects only indigenous wetlands, which it defines as wetlands with more than 50 percent native plant cover.
Conservation groups say the plan is out of kilter with the RMA and does not comply with its broader definition of a wetland.
Kevin Matthews, of the Bushland Trust said the few protections there were in the plan were being flouted repeatedly.
He said landowners wanting to dig for kauri got around the restrictions by draining and spraying wetlands with herbicide, and letting the weeds take over so they could no longer be classed as indigenous.
Mr Matthews said that had happened many times in the Far North, and caused irreparable damage, when miners broke through the hard iron pan that previously nourished the wetland by preventing surface water from draining away.
"The biggest problem is that the regional council only becomes involved once somebody reports it," he said.
"It's after the fact, ad hoc stuff. The damage is done; the council becomes involved, but often it is too late for the wetland."
Mr Matthews said a case in point was Lake Ngatu, where landowners had drained a nearby wetland to dig for kauri, and re-opened an old gumdiggers' drain into the lake.
The council had intervened too late to stop the pollution of the once-pristine lake and damage to beds of kuta, a reed highly prized by Maori weavers, he said.
Maori who have kaitiaki responsibilities for Waipoua kauri forest have their own objections to the swamp kauri trade.
Will Ngakuru, of Te Roroa, said there was a fear that trucking ancient logs from the Far North to Whangarei could spread the disease that was killing living kauri.
"The fact that we're digging up these trees, that existed in kauri ecosystems, and then we're transporting that soil all over the north, is a concern," he said.
Mr Ngakuru said he had followed the trucks carrying giant swamp kauri stumps and logs, and seen soil dropping off the trucks.
He said the die-back disease killing living kauri was caused by a micro-organism that spread through soil.
Northland Regional Council chairman Bill Shepherd said the council's Water and Soil Plan was written some years ago and was currently under review.
He said staff could only administer the rules relating to wetlands as they stood at present, but he urged Maori unhappy with the plan's limitations to speak up and make submissions when the time came.
But Mr Shepherd agreed with Maori leaders calling for the swamp kauri export trade to be stopped.
"It doesn't really make any economic sense. Even if you ignore the taonga aspect of it from the Maori perspective, it makes no sense to be exporting 50,000-year-old kauri stumps; logs, whatever, as a raw unprocessed product," he said.
"It's a once in a lifetime treasure, and we shouldn't be doing it."
The Minister for Primary Industries has said the swamp kauri export trade is good for New Zealand, but has asked his officials to advise him on improvements that could be made to the way it's regulated.