Ngati Whatua says it will refuse to take part in any powhiri for international trade ministers when they visit New Zealand to sign the Trans-Pacific Partnership on February 4 because it opposes the agreement.
Piripi Davis, chairman of the tribe's Orakei trust board, said its "strong opposition" to the TPP meant it would not participate in welcoming ceremonies when ministers from the 12 TPP countries gather in Auckland for the signing.
A spokeswoman said the iwi had not yet been asked if it would take part in the powhiri, but in the past it had done so for visiting dignitaries as it had mana whenua status in central Auckland.
It was letting the Government know ahead of time that it would not take part.
Mr Davis said the iwi had supported New Zealand's bid to win a seat on the United Nations Security Council.