Chinese media say two Canadian nationals are being investigated for suspected theft of state secrets.
The allegations relate to China's military and defence research, but the reports gave no other details.
The suspects are identified in Chinese state media as Kevin Garratt and Julia Dawn Garratt, a couple who have reportedly run a popular coffee shop since 2008 in China's northeastern city of Dandong, which borders North Korea.
Canadian Foreign Affairs says it's aware of reports two Canadians have been detained in China and is trying get more information. The department says consular officials are ready to provide assistance.
Last week, Canada blamed Chinese hackers for infiltrating computers at the National Research Council of Canada, something the Chinese embassy in Ottawa denied.
A spokesman for Foreign Affairs Minister John Baird says the minister took up the matter with Chinese officials in Bejing during his visit to Asia.
"The minister took the opportunity to discuss the situation with his counterpart, and they had a full and frank exchange of views on the matter,'' said Adam Hodge.