Mounties guarding Parliament Hill will soon be armed with submachine-guns as part of the force's move to beef up security at the centre of Canada's government.

RCMP officers on duty on the Hill currently carry handguns as primary weapons, while their secondary weapons, shotguns, are stored in vehicles.

The force confirmed Wednesday the Heckler & Koch MP5 will be reintroduced in the next few months once its officers are trained to use them.

RCMP Sgt. Greg Cox said the MP5s are more accurate and have a better range capability as opposed to a shotgun, which fires a round that often spreads beyond its intended target.

The Mounties carried MP5s in the 1980s to guard Parliament Hill and embassies, but the firearms were phased out.

The submachine-guns, like the Mounties' current secondary weapon, won't be visible and will only be pulled out if needed, Cox added.

"The one instance that comes to mind is that there may be a shooter inside one of these buildings randomly shooting targets," he said. "This is a better suited option to deal with that threat."

Embarrassing security breach

The move follows a two-month review of an embarrassing security breach for the Mounties in December, in which 19 Greenpeace activists climbed onto the roof of the West Block of Parliament and unfurled banners calling for action on climate change.

Despite the fact that the protest was peaceful, the Dec. 7 incident revealed a serious weakness in Parliament security and shows a need for increased measures, said expert Michel Juneau-Katsuya, a former senior intelligence officer at the Canadian Security Intelligence Service.

"Where they were on the top of a roof was an excellent place for a sharpshooter to be capable to position himself in a place where he could have targeted any politician going in, including the prime minister," Juneau-Katsuya told CBC News.

In addition to the new weapons, more security cameras and alarms will be installed inside Parliament, while House of Commons constables will be getting bullet-proof vests. They are currently only equipped with a baton, handcuffs and — since the H1N1 pandemic — hand sanitizer.

The Commons constables will still be unarmed to preserve the image that Parliament is accessible and welcoming.

Juneau-Katsuya said the moves are about keeping a balance between an open democracy and preserving security in the wake of the Sept. 11, 2001, attacks in the United States.

"Turning the place into a bunker would give a victory to the terrorists at the end of the day," he said.