MINNEAPOLIS — The public authority overseeing construction of a new Minnesota Vikings stadium warned Friday that the opening could be delayed if the team doesn’t quickly resume negotiations on lease and development agreements.

Minnesota Sports Facilities Authority chairwoman Michele Kelm-Helgen said the team unexpectedly broke off negotiations a day earlier, saying it wanted to wait until a review was completed on its ability to finance its $477 million share of the nearly billion-dollar stadium.

Kelm-Helgen said the agreements need to be in place by Sept. 15 to avoid delays. The project timeline calls for breaking ground on the taxpayer-subsidized stadium on Nov. 7 and completing it ahead of the 2016 football season.

Kelm-Helgen wouldn’t identify the major issues separating the two sides on the agreements, calling them “substantial” but well within reach. At the authority’s regular meeting Friday, she said it was a surprise when the Vikings broke off talks. Delay in those agreements would delay the team’s financing and eventually a state bond sale.

“We felt like it was important we have an alert that our (construction) schedule could be in jeopardy,” Kelm-Helgen said. That could eventually mean cost overruns for taxpayers.

Vikings spokesman Lester Bagley said the team was confident the stadium would stay on schedule. But he said the due diligence review was having a negative effect on the talks, an allusion to the closer examination of owners Zygi and Mark Wilf’s family finances after a New Jersey judge found they had defrauded a business partner in a past development deal. Gov. Mark Dayton has said his confidence in the Wilfs was shaken and said an audit was necessary before the public commits $498 million of taxpayer money.

“We can’t have partnership negotiations when we’re not at the table as partners,” Bagley said.

The New Jersey judge is expected to rule soon on the damages the Wilfs will have to pay. But Bagley said again Friday the lawsuit “will have absolutely no impact” on their ability to pay their share of the stadium.

Bagley said the team has provided detailed financial information for the authority and arranged meetings involving the NFL and several banks, including U.S. Bank.

“Both the NFL and the banks have said unequivocally that the Wilfs have the financial wherewithal to finance this project,” Bagley said.

The $975 million stadium project was approved by the Legislature in 2012 with a strong push from Dayton, who warned that the team could leave the state without a new building. And despite the cloud raised by the New Jersey lawsuit, both Dayton and Kelm-Helgen have said they see no way the stadium doesn’t move forward.

An Associated Press review of contracts this week found millions have already been paid or committed, even before ground has been broken.

The team is entering its final season in the Metrodome, its home for more than three decades. The Vikings are planning to play two years at the University of Minnesota’s on-campus stadium before its new home is ready, assuming it is constructed on schedule.