The first serious look at the feasibility of a stadium in downtown Auckland should be completed mid-year.
The Auckland Council's Regional Facilities Agency (RFA) has commissioned an initial study on whether the idea is viable to eventually replace Eden Park.
Mayor Phil Goff believes the site with the best chance is former railway land owned by Ngati Whatua adjacent to Vector Arena, near the waterfront.
"There's a lot of work to be done and time is on our side to look at this, and it may be that it doesn't work as a stadium site," Mr Goff said.
He said he did not see a new stadium as a priority for ratepayer spending, but said commercial backers and a government contribution could make it possible.
The study by consultants PWC was likely to cost several hundred thousand dollars.
RFA chief executive Chris Brooks said the initial study would not look at the future of Eden Park, but if a new stadium appeared viable that would be a part of further investigation.
Eden Park was owned by a Trust Board controlled by the government, cricket and rugby bodies, with council guaranteeing $46 million of its debt.
Mr Goff said RFA had told him Eden Park would need upgrades that could cost $250 million in 15 years.
Trust Board chair Doug McKay last year expressed displeasure at the stadium debate occuring without it being involved.
Mr McKay has been unavailable for comment and Mr Goff would not discuss the chair's views expressed in a conversation with him about the stadium plan.