Auckland Mayor Phil Goff has ordered the council to look into alternative sites for a stadium to replace Eden Park.
"We know that in about 15 years there'll need to be major work done on the Mt Eden stadium if it's to be retained," he told Newshub.
"And yet it has significant problems - it can't run concerts or night events for more than 21 nights a year. It's underutilised and it's not meeting the cost of depreciation."
Eden Park is surrounded by residential properties in the suburb of Sandringham.
"We need to scope out what's going to happen in 15 years' time, when either there'll be a quarter of a billion dollars spent on Eden Park to replace the north stand, or we would have to look at alternatives. And one of the alternatives often talked about is a CBD stadium."
He's asked Regional Facilities Auckland to scope out options for an alternative stadium site. One potential location is behind the old downtown railway station near Vector Arena.
A year ago, then-Prime Minister John Key ruled out any taxpayer funding for a new Auckland stadium.
Mr Key said the Government had "no appetite" for it, after spending nearly $200 million to upgrade Eden Park before the 2011 Rugby World Cup.
"Obviously the cost of building a new stadium would be considerable," Mr Goff says.
"It's not a priority for Auckland at this time - we're looking at transport infrastructure, we're looking at infrastructure to allow more housing to be built.
"But it's better to plan ahead, and look at what the options are now than leaving it to the last minute, and finding that those options no longer exist.
"At least we'll know what the option might be, and what the potential cost might be to that alternative site."