The city is offering a lending hand of more than $30 million to one of the city’s largest developers, as it plans to be the anchor tenant in a proposed Queens office tower.

Adding more government support to the development in Long Island City would spark the construction of the 650,000-square-foot building, which has been slow to take off, officials said at a City Council hearing yesterday.

People familiar with the planned building say the project has lagged because development company Tishman Speyer has been unable to find a large tenant to anchor the building, and did not want to proceed without assurances that a good portion of the building would be leased.

“The hope is that with the first building constructed, Tishman would then be able to attract private sector tenants to the rest of the building,” an executive vice president at the city’s Economic Development Corporation, Seth Pinsky, said.

Especially in today’s hot real estate market, government assistance to projects has drawn ire from watchdog groups, who claim that developers are frequently offered overly generous subsidies.