Canada's foreign ministry said it was "aware of a Canadian citizen" having been detained, according to the National Post, which cited a ministry spokesperson.
The spokesperson did not provide further details and did not suggest that the detention was linked to the arrest of Huawei chief financial officer Meng Wanzhou, the report said.
Chinese foreign ministry spokeswoman Hua Chunying told a regular press briefing that she had "not heard" about the reported detention.
The recent detentions of two Canadians has raised suspicions that Beijing is holding them in retaliation for Meng's December 1 arrest, though no link has officially been made between the cases.
Meng was released on bail last week in Vancouver pending a US extradition hearing on US fraud charges related to sanctions-breaking business dealings with Iran.
China has accused the other detainees -- former Canadian diplomat Michael Kovrig and China-based business consultant Michael Spavor -- of activities "that endanger China's national security".
They were both detained on December 10.
Kovrig is a Hong Kong-based senior adviser at the International Crisis Group think tank, while Spavor facilitates trips to North Korea and helped former NBA star Dennis Rodman travel to the neighbouring country.
Beijing has threatened Canada with "grave consequences" if Meng is not freed and Chinese state-run media has lashed out at the arrest, saying it was politically motivated.
Ottawa has repeatedly said the arrest was not political but rather a judicial process in keeping with an extradition treaty with Washington. (AFP) CPS
(With inputs from agencies.)