The board representing Maori in Auckland is questioning the legality of the sale by the council of a prime piece of downtown land.
The Independent Maori Statutory Board said Queen Elizabeth Square near the waterfront might not be the council's to sell.
The council could be within a week of doing a deal to sell the square.
It is part of a wider deal with Precinct Properties, which is redeveloping the buildings around the square.
Maori board chairperson David Taipari has asked the council to detail the history of the reclaimed site, which was transferred to the council from the former harbour board.
The council said there were no Treaty issues regarding the land, and Ngati Whatua said it was not aware of any entitlement to the site.