As the government prepares to make the case for its controversial proposal to turn over security control of the parliamentary precinct to the Royal Canadian Mounted Police, some MPs are already expressing concern over the plan.

Green Party Leader Elizabeth May said Thursday she agrees that co-ordination is needed between the various forces operating in and around Parliament Hill.

"Absolutely, let's get everyone on the same radio frequency," she told CBC News — but added she doesn't like the suggestion that the RCMP lead parliamentary security, particularly after the events of Oct. 22, when gunman Michael Zehaf-Bibeau stormed Parliament Hill.

"We know who the heroes were for Oct. 22 — they were the House of Commons security guards inside, led by our former sergeant-at-arms, Kevin Vickers," she said.

It looks as though the heroes are being demoted and the people who missed the shooter running in are being put in charge - Elizabeth May, Green party leader

"It was an unarmed [House] security guard, Samearn Son, who personally tackled a man with a loaded gun who had, by the way, just run by a whole lot of RCMP cars that sit outside this place all day long ready to spring into action."

Those RCMP officers "sprung into action all right when [NDP Leader] Tom Mulcair ran a stop sign," she recalled. "But they somehow didn't notice the man with a gun."

She said she isn't condemning the RCMP. "Everybody can make mistakes," she said.

"But based on this incident it looks as though the heroes are being demoted and the people who missed the shooter running in are being put in charge."

May also questioned whether the move could encroach on parliamentary independence.

"It's not at all clear that we are not about to lose the integrity of the separation of Parliament from government," she said.

'This government wants to control everything'

Independent MP Brent Rathgeber echoed those fears.

In December, the House of Commons paid tribute to security guards for their efforts during the Oct. 22 shootings. (Adrian Wyld/Canadian Press)

"Parliament is separate and independent from the Crown or from the government," he said.

"The RCMP is the government's police force — it gets its funding through the public safety minister, and is accountable to the House through the public safety minister."

Given those dynamics, he said, the RCMP "is part of government," while Parliament "is supposed to be independent of government" — which is why the House and Security forces are ultimately accountable to the House and Senate speakers.

"I think it's symbolic of how the government treats this place," he said. "This government wants to control everything."

Government whip John Duncan did his best to downplay those worries.

RCMP would become more 'visible'

"We have a very well-trained, respected House of Commons and Senate security force that will perform many of the functions they currently perform," he told reporters.

He acknowledged that the RCMP presence would become more "visible" if the plan goes forward.

"Right now … the security detail for the prime minister, which is RCMP, has to be invited in [to Parliament] on a daily basis," he pointed out.

"[The motion] eliminates the need for day-by-day Speaker invitations. That would all be clarified."

The first round of debate over the government's motion to "invite" the RCMP to take over operational security is scheduled to get underway on Friday, but likely won't go to a vote until MPs return from their constituency week on Feb. 16.

The Senate also has to sign off on the proposal before it can go forward.