VANCOUVER, Feb 3 (Reuters) - The head of security for the Winter Olympics said on Wednesday he is not aware of any specific terror threat to the Vancouver Games, which should allow him to stay within the C$900 million ($850 million) security budget.

"There is absolutely no known threat to the Olympic or Paralympic Games," Bud Mercer, an assistant commissioner of the Royal Canadian Mounted Police told reporters in a briefing on security plans for the Games, which start Feb. 12.

Some 15,000 police, soldiers and private guards are being used in Vancouver and the mountain resort of Whistler in one of the largest security operations in Canadian history, most of which is being paid for by the federal government.

"I would suggest that, based on today's environment, unless there is a change either domestically or internationally, I would suggest we are able to stay within the C$900 million,"Mercer said.

He dismissed a suggestion that too much is being spent on security, given the low threat level. Planners assumed a moderate threat level when they drafted plans for protecting the 17-day event in February and the Paralympics in March.

"As I have said publicly before, I don't think there is a parent in the world who is sending a child here ... who doesn't expect them to come back safely," Mercer said, calling the security plans "balanced."

Mercer said if there is an attack or other serious incident at the Games he is equipped to bring in additional forces, which could increase the costs.