While the U.S. and other countries have publicly called out Chinese-owned firms as being among the dangers, Vic Toews said he sees no reason to name names — at least right now.
"If there is a national security interest that requires disclosure of some of these names and companies, that will be done in due course," Toews said.
"At this time I don't see simply making general allegations without talking about why I would be saying that."
Toews admitted that some countries pose a greater risk than others, but wouldn't say which ones are of particular concern.
"I don't think that's going to serve any particular purpose calling out any particular country at this time," he said.
"I'm certainly aware of where threats come from and we are constantly being briefed by our allies on developments in that respect."
One firm under scrutiny around the world is the Chinese telecom giant Huawei, which is already active in Canada and could be in a position to bid on upcoming government contracts.
Australia has already barred the firm from doing government work there and a report from a U.S. congressional committee earlier this month suggested the firm should be equally prohibited from doing similar work in the U.S.
Toews won't say whether Canada will follow America's lead.
"The Americans make their own decisions, we make our decisions," he said. "We certainly look at what the Americans are doing and consider that but we will make decisions in the best interests of Canada."
NDP Leader Tom Mulcair said the Conservatives need to be a lot clearer about what criteria are in play when they make decisions about the involvement of foreign countries or companies in Canada.
He said it seems so far like the Tories are improvising.
"We should be putting our cards on the table and saying if those national security concerns exist, we've got to define them," Mulcair said.
Acting Liberal leader Bob Rae also urged the government to provide details.
"I think the issue of cybersecurity is something that we need to discuss in a very transparent way," Rae said.
"If the government has information that says, 'Here are the agencies around the world that are posing a threat, or pose a risk for us, we think they've engaged in this kind of activity or that kind of activity,' then we should name names."
Toews made the remarks as he announced $155 million over five years to reinforce the federal government's infrastructure and networks to better protect against cyber threats.
The money, already earmarked in the budget, comes on the heels of last week's stunning guilty plea from Canadian Forces Sub-Lt. Jeffrey Paul Delisle, who was facing charges of espionage and breach of trust for selling classified information to Russia from 2007 to 2012.
Delisle had been employed as a threat assessment analyst at Trinity, a highly-secretive military facility in Halifax.
His position gave him access to intelligence shared by the Five Eyes group, which includes Canada, Great Britain, the United States, New Zealand and Australia.
Delisle had been slipping the Russians information obtained off his work computer.
The money announced Wednesday also comes ahead of an auditor general's report assessing whether federal organizations are doing enough to protect itself against cyber threats.
Last year, hackers managed to force the Finance and Treasury Board departments offline after an employee clicked on a link in an email that allowed outsiders to infiltrate government systems.
The auditor general's report is scheduled to be released next week.
Rae said the government needs to get better at keeping ahead of the cyber criminals.
"All governments around the world are having difficulty keeping up with the pace of tech change and with the pace of the technologies that are available to the people who want to break down systems and break into systems and commit effectively what are cyber crimes," Rae said.
"Government is not supple enough and government is not quick enough to respond to these things and the people who are doing what they are doing out there are very quick and very supply and very fast."
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