The status of Maori as the country's indigenous population could be in danger if research, which suggests previous civilisations lived in New Zealand before Maori arrived, is proved true.
Ngapuhi leader David Rankin said books by authors such as investigative journalist Ian Wishart and historian Noel Hilliam presented "clear evidence" that some of New Zealand's earliest residents might have arrived before the Polynesians.
He pointed to numerous Maori oral histories which referred to people being here when the first Maori arrived, including fair-skinned people.
"If we believe our histories, then we as Maori are not the indigenous people of New Zealand."
The archaeological evidence in some research was a potential challenge to the status of Maori as indigenous, which was why he believed no other Maori was prepared to speak publicly on the issue, Mr Rankin said.
Details of much of the country's past was being concealed by academic historians, he said.
"I would say it's a conspiracy. They are worried that their own research will be exposed so they have worked hard to ridicule and suppress any Maori history which disagrees with their views.
"However, the tide is turning and more people are now seeing that there is a whole history of our country that has been concealed and which will have major implications for Treaty settlements for example."
To the Ends of the Earth, a book Mr Hilliam co-wrote with New Zealand pre-historians Maxwell C Hill and Gary Cook, published earlier this year, detailed evidence the authors said convinced them that Greek-Egyptians and others sailed to and settled New Zealand long before the arrival of Maori.
The 378-page book showed ancient maps detailing the coastlines of Australia and New Zealand and first drawn before the birth of Christ. Skeletons, rock carvings, stone buildings and monuments and oral tradition all attest to people of European origin living here for centuries before the arrival of Polynesians, the authors said.