Nassau County Executive Edward Mangano said Tuesday that the reopening of the Nassau Coliseum could be pushed back from mid-December until early 2017.

In remarks to the Long Island Association, the region’s largest business group, Mangano said the $260.5 million, privately funded project would open in the “first quarter of 2017. Maybe we’ll get lucky and it will be a little bit earlier.”

Project developer Bruce Ratner, executive chairman of Forest City Ratner Cos., has targeted the Coliseum reopening for no later than Dec. 10 when the University of Kentucky men’s basketball team is scheduled to play Hofstra University in the first game at the renovated arena.

A clause in the Hofstra-Kentucky contract calls for the game to be moved to Barclays Center if the Coliseum is not ready.

Mangano said Ratner faced delays in reaching a deal with local labor unions to begin work on the arena, pushing back the start of construction from August to November.

The development’s “anticipated completion date is December 2016 but they alerted us that the delay in reaching an agreement with labor may push the opening to the beginning of 2017,” Mangano said.

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John Durso, president of the Long Island Federation of Labor, said unions are not to blame for the delays.

“Labor was ready, willing and able to start the project on time,” Durso said. “The delay was not caused by us.”

Ratner spokeswoman Ashley Cotton said the company still expects to reopen the Coliseum “by winter of 2016.”

In October, Mikhail Prokhorov, owner of the Brooklyn Nets basketball team, purchased a controlling stake in Nassau Events Center, the company redeveloping the Coliseum.

Ratner maintained a 15 percent ownership in Nassau Events Center, the company heading the redevelopment, and will remain the lead developer on the Coliseum project.

Nassau Events plans to redevelop and downsize the arena to 13,000 seats, and construct an adjacent complex with a movie theater, restaurants and stores.

The Nets’ new D-League team is expected to move to the Coliseum for the 2017-18 season. Nassau Events’ lease with the county also calls for the firm to bring an American Hockey League minor league team to the arena, but the identity of that team has yet to be disclosed.