OTTAWA - Prime Minister Stephen Harper says Canada will continue to navigate its "complex" commercial relationship with China despite national security worries.

"The Chinese have obviously very different systems than we do - economic and political systems - and that's why obviously some of these particular transactions raise concerns," Harper told reporters in Dakar, Senegal, where he was on an official visit.

He was responding to a question on Canada's business dealings with Chinese company Huawei, though he wouldn't address specific accusations the telecom giant poses a national security threat.

"We will ensure as a government that we have not only a growing relationship with China, but a relationship with China that is in Canada's best interests, that always serves the broader interests of the Canadian economy, and that's how we look at all of these matters. And, of course, as you know, there is a national security dimension to this relationship - in fact, to all of our activities that we take very seriously."

Huawei - one of the world's largest telecommunications companies that operates in 140 countries, including Canada - has come under increased scrutiny following a scathing US congressional report released Monday that raised concerns its technology could be used by the Chinese government for cyber-espionage.

The Chinese government and Huawei have both denied the telecom is being used for espionage and have called the allegations in the congressional report baseless.

Still, Harper's comments come as Western governments and intelligence agencies raise warnings about the growing dangers lurking in cyberspace.

In a speech Thursday, US Defence Secretary Leon Panetta talked about a major computer virus called Shamoon that destroyed over 30,000 computers at Saudi Arabian oil company Aramco, and warned of unnamed foreign actors that were targeting his country's computer control systems that operate chemical, electricity and water plants in the United States.

In Canada, energy industry giant Telvent admitted in September it had been the victim of a cyber-security breach of its computers - an attack linked by experts to the Chinese.

The Conservative government is also weighing whether to green light China-owned CNOOC's proposed takeover of energy company Nexen after granting itself a 30-day extension on the decision Thursday.

The NDP opposes the takeover on environmental and human rights concerns, as well as on national security grounds.

--with files from Reuters