The Canadian Consulate in Hong Kong has banned its staff from travelling outside the city, including mainland China.
It comes as the Chinese government announced this week that British Consulate employee Simon Cheng Man-kit has been held in neighbouring mainland city of Shenzhen.
The recent development has stoked tensions in Hong Kong, which has been gripped by months of anti-government protests.
"At present, locally engaged staff will not undertake official business travel outside of Hong Kong," the Canadian Consulate said in a statement on Friday.
The consulate did not clarify whether the travel restriction was directly related to the detention of the British Consulate staffer.
Mr Cheng Man-kit went missing two weeks ago after he went on a business trip to Shenzhen from Hong Kong's high-speed cross-border rail terminal.
He said this week that he had been placed in administrative detention for 15 days for violating public order regulations. It did not elaborate.
Mr Cheng Man-kit had worked for the British Consulate since December 2017 as an international trade and investment officer for the Scottish government.
He and other local staff at consulates and embassies support diplomats but don't have diplomatic passports themselves.
The Global Times, a Communist Party-owned nationalistic tabloid, reported on Wednesday that Mr Cheng Man-kit was detained for "soliciting prostitutes."
Police in Shenzhen did not respond to requests for confirmation of the report.
China often uses public order charges against political targets and has sometimes used the charge of soliciting prostitution.
Ou Shaokun, an anti-corruption activist, alleged in 2015 that he was framed by authorities in southern Hunan province who said they found him in a hotel room with a prostitute.
The Canadian government also updated its travel advice for China on Thursday to warn of stepped up border checks on phones.
"Increased screening of travellers' digital devices has been reported at border crossings between mainland China and Hong Kong," the advisory said.
There have been increasing reports that Chinese immigration officers are inspecting phones for photos related to the Hong Kong protests.
