OTTAWA - A national policy spelling out when RCMP officers should call for backup could cost tens of millions of dollars and force police officers to live closer to where they work.

But the Mounties need more time to establish the new policy, says Deputy Commissioner Bill Sweeney, because of the enormous costs and logistics involved.

"The implementation of this plan will require a period of time, given the challenges of resources and residencies,'' Sweeney told a news conference Wednesday.

The current policy came under review following two fatal shootings of lone RCMP officers this fall.

Const. Doug Scott was killed early last month while answering a drunk-driving call in the tiny Nunavut hamlet of Kimmirut. Police have said the 20-year-old officer was shot before he could even get out of his car.

In October, Const. Christopher Worden was killed while responding to a call at a residence in Hay River, Northwest Territories.

Since then, critics have raised concerns about sending young, inexperienced officers to remote postings with little support.

A new policy could mean new requirements to force Mounties to live close to the communities where they work, said Sweeney.

"Today RCMP officers can choose where they live, for the most part, he said.

"With a national backup policy, the employer, the RCMP, may impose restrictions on that.''

However, policies can't replace common sense and good judgment, the deputy commissioner said.

Mounties work in a variety of elements, policing entire provinces as well as small towns and northern villages and they have to judge dangers every day, he said.

Officers shouldn't hesitate to call for help if they need it, but at the same time, they can't leave people at risk while they wait for backup, Sweeney said.

"We cannot simply stand by and allow the public to be at risk to wait for a backup, in some circumstances,'' he said.

The new policy could mean redeploying resources to smaller centres which may only have two Mounties on hand, with an aim of reassuring officers of their safety.

But Sweeney stressed that no policy will eliminate risks.

"Our society is full of risks virtually everywhere,'' he said.

"There are people who become careless and cause problems. There are others with criminal and evil intentions who don't care who is harmed on their way to getting what they are seeking, whether it be money or drugs.''

It's unclear when a final policy would be adopted by the Mounties.

Also uncertain is the final price tag, which Sweeney estimates could reach into the "tens of millions of dollars.''