CARY - Long-delayed plans for a 10-story office tower in southeast Cary live on, but the developer says it could take five more years to build what would be one of the town’s tallest structures.

The project’s groundbreaking has stalled long enough that Regency Park Office Development had to request a deadline extension from the town of Cary last week. The town government’s 2004 approval of the project was set to expire this month, but a Cary Town Council vote on Thursday allows Regency until September 2017 to make “substantial progress” on the building.

“We want to finish what we started,” developer Edward Woolner told the council. But financing may not be available until 2016 or 2017, he said, “and I just don’t happen to have $65 million” available.

If it materializes, the project would put about 281,000 square feet of office space at the southeast corner of Tryon Road and Regency Parkway, near WakeMed Cary Hospital. The site is one of the last open spaces in the Regency Park area, which has grown since 1979 to house more than 1.25 million square feet of office space and several thousand employees, Woolner said.

The developer has long planned the proposed glass-walled tower as a “signature office building,” said William Brian, an attorney for the developer, but “economic circumstances have made it impossible to move forward.”

Regency has already spent more than $400,000 on plans, according to the company.

Construction of the project could also put a heavy bill on the town. Office traffic could push nearby roads to their capacity, requiring the town to pay up to $2.3 million for road improvements, according to a town report.

The developer would contribute about $350,000 in transportation impact fees, said Director of Engineering Tim Bailey.

Councilwoman Gale Adcock said she was worried the project would require such expensive upgrades to nearby roads.

“What concerns me about this is ... we don’t have this money set aside,” Adcock said.

Councilman Don Frantz pointed out that the developer had designed the project as part of its larger park long before other uses began to burden the nearby roads.

But Bailey said the project may not cause as much traffic as projected – only time would tell, he said.

The council unanimously agreed to extend the project’s deadline.