The case unfolds amid high tensions between Ottawa and Beijing over China's prolonged detention of Canadian citizens Michael Kovrig and Michael Spavor for alleged spying.

"The U.S. has been taking advantage of Canada, and the U.S. is the trouble maker of China-Canada relations," the Chinese envoy to Ottawa, Cong Peiwu, told Reuters in a telephone interview.

China's telecom operators must now use facial recognition technology and other means to verify the identity of people opening new mobile phone accounts.