Security costs for the Republican National Convention (searchthis summer will hit $76 million, police Commissioner Ray Kelly (searchsaid Monday.

Just last month, the estimate was $47 million to $65 million.

The estimated cost of police overtime alone will be a staggering $59 million for the four-day gathering, Kelly told the City Council's Public Safety Committee.

The city, just emerging from successive years of multibillion-dollar budget gaps, will likely have to pick up at least two-thirds of the convention's security cost — which is even more than the $64 million organizers are raising to bring the convention to the city. No host committee funds would be used for security.

The federal government has committed about $25 million for security for the convention, at which President Bush (searchwill be nominated for a second term. The convention is scheduled to begin Aug. 30 at Madison Square Garden.

Kelly said the city was trying to get more federal funds for security.

"We're talking to the federal government, the legislative branch, the executive branch, and we're hopeful that we will (get more money)," he said.

In March, he said the $25 million was "a fair amount."

A few months ago, Mayor Michael Bloomberg (searchpredicted that $27 million would cover not only security at the convention but also sanitation and insurance.

That estimate has escalated rapidly, as the police department, which has about 36,500 members, has budgeted a more intense regimen — of counterterrorism, crowd control and civil rights training — to more officers in recent months.

Kelly said Monday that the police department will use 6,000 to 10,000 officers to handle the convention and the expected demonstrations around Madison Square Garden.

Those officers will receive overtime training to prepare for chemical, biological or radiological attacks. The current class in the Police Academy is receiving similar training in preparation for the convention.

In June, 10,000 officers will be trained in legal issues, including the rights of demonstrators, in addition to disorder control, subway track safety, hazardous materials and terrorism awareness.

The police department also plans to buy a closed-circuit television system, special crowd control barriers to ring Madison Square Garden, nuclear, biological and chemical detection and monitoring devices, 300 motor scooters and 15 vans for the gathering.

And while the convention is going on, the U.S. Open tennis tournament will be in town and the New York Mets, New York Yankees and New York Liberty will play home games.

Boston, which is hosting the Democratic convention, has estimated its security costs at $40 million. It also has been allotted $25 million by the federal government for security.