GATINEAU, Que. — A flirtatious email exchange between a Tory MP and a Chinese journalist has to be taken seriously, because China views foreign politicians as top targets, a former Chinese spy said Wednesday.

Defector Li Fengzhi said agents of China's Ministry of State Security -- where he used to work -- often focus on politicians.

Li was commenting on the case of Conservative MP Bob Dechert, who has admitted to sending flirty emails to a female correspondent for the state-controlled Xinhua news agency. Dechert is parliamentary secretary to Foreign Affairs Minister John Baird.

"Yes, the Canadian government should pay attention to this, to this kind of issue," Li told a conference on espionage, speaking via video link from a secret location.

Li said not all Chinese journalists are spies, but politicians are prime targets.

The head of the Canadian Security Intelligence Service was rebuked last year when he suggested Chinese agents were influencing some provincial politicians.

CSIS head Dick Fadden later downplayed his comments, but they echoed when the incident involving Dechert and Shi Rong, Xinhua's chief Toronto correspondent, became public knowledge last summer.

Shi has since been recalled to Beijing.

Li suggested CSIS likely knew more about the case than it was willing to say openly

Neither CSIS nor the RCMP has commented publicly on the matter.

Li defected in 2009, so he said he has no direct knowledge of the case, but he read numerous stories about the matter before he gave his keynote address Wednesday to a packed hotel ballroom on the far side of the Ottawa River from Parliament Hill.

He said targeting politicians is "the normal way to get the job done" for Chinese spies and they commonly pose as reporters when posted abroad.

Li said he believes Shi "possibly had some relationship with the security services" even if she wasn't an actual spy.

But now that she is back in China, she is likely getting lots of attention from the Chinese espionage apparatus, he said.

"Other agents should try to get close to her ... to use her as a bridge to get intelligence from the politician."

He said the main goal of Chinese spies is to learn "how to influence the politician," for example to get him to speak out on China's behalf. They also want to plant seeds "to influence this gentleman to do something, say when he's doing some policy-making."

Prime Minister Stephen Harper, who is expected to travel to China next year as part of Canada's continuing re-engagement with the Asian economic giant, has said he doesn't believe Dechert compromised Canadian interests.

Dechert has insisted his relationship with Shi was an innocent friendship

Baird has also said he stands by his colleague.

Xinhua, which was created by the Chinese Communist Party in the 1930s to handle revolutionary propaganda, has grown into a multimedia empire with offices across the world and throughout China. It is run by the Chinese government in Beijing.

It is also widely known by western intelligence agencies to have links to China's intelligence services.