OTTAWA -- Personal and political divisions over ballistic missile defence were on clear display Tuesday, as a group of parliamentarians gathered on Parliament Hill to discuss the threat posed by North Korea.

Members of the House of Commons' defence committee agreed during a rare summer meeting to a series of emergency briefings in the coming weeks on the government's plan should North Korea attack.

The meeting came as the U.S. Treasury Department upped the ante on North Korea by sanctioning several Chinese and Russian entities for supporting the rogue state's nuclear and missile programs.

There was no immediate word of Canada following with its own sanctions.

Instead, much of the discussion in the hallways before and after the committee meeting centred on whether Canada should join the U.S. continental missile-defence shield, after famously opting out of the system in 2005.

The Trudeau government has sidestepped questions about Canada's intentions, saying only that ballistic missiles are one threat being discussed as Canada and the U.S. look to upgrade North America's defences.

But one Liberal MP said Tuesday that Canada should reconsider its decision not to join the U.S. missile shield, even as the Conservatives danced around the issue and the NDP reaffirmed its historic opposition.

Liberal MP Mark Gerretsen said a lot has changed since then-prime minister Paul Martin decided Canada would not join ballistic missile defence in 2005.

"Personally, I think that we do need to start to look at what Canada's role will be in that," he told reporters after the committee meeting.

"We should be having an ongoing discussion about what our role should be in that. And I think 10 years plus after the fact is a timely opportunity to have that discussion again."

'Cheaper to develop new weapons'

Gerretsen would not comment on the government's official position, or whether his view was shared by many other members of his party.

But fellow Liberal MP Stephen Fuhr, chairman of the defence committee, noted that Canada has limited resources when it comes to defence -- a reference to the fact the U.S. has spent about $100 billion on its missile shield.

Fuhr also played down the threat posed by North Korea, citing military officials and defence experts who told the committee last year that there was no direct threat to Canada from another country.

"Even if we wind back the media in the last 30 days, I don't think Canada was ever mentioned in the rhetoric that was flying back and forth between North Korea and the United States," he said.

Meanwhile, Conservative MPs refused to say Tuesday where their party sits now.

The Liberals were in office when Canada declined to join the defence system in 2005, but Stephen Harper made no move to reverse course during the Tories' 10 years in power.

That was despite Conservatives having pressed for Canada to join while they were in opposition to Martin's government.

Conservative defence critic James Bezan suggested his party would take a position once the defence committee is briefed on North Korea, even as he referenced the fiery debate from 12 years ago.

"You've got to remember the history behind that discussion, the wounds that were created because of the decision by Paul Martin back in 2005. And things didn't change until this summer," Bezan added.

"So from this point forward, everyone is looking at how we can best work with the United States. How we can work through NORAD in dealing with this new threat."

The only party with a clear position appeared to be the New Democrats, with NDP foreign affairs critic Helene Laverdiere calling on the Liberals to reaffirm their opposition to ballistic missile defence.

"It's cheaper to develop new weapons than to develop that kind of defensive system," she said.

"And that kind of defensive system only leads countries like North Korea but also countries like China and Russia, who may feel concerned, to upgrade their systems and it leads to escalation."

Laverdiere called for Canada to take more of a leadership role in finding a diplomatic solution and to support efforts at the UN for full nuclear disarmament around the world.