Foreign Affairs Minister Chrystia Freeland says the government is working on contingency plans to assist Canadians in Hong Kong, where an escalating political conflict has resulted in mounting protests, including recent demonstrations at the airport.

Hong Kong's airport resumed operations on Wednesday after hundreds of flights had been disrupted as pro-democracy protesters clashed with police.

People have been protesting in Hong Kong since early June over proposed extradition legislation that could have sent suspects to mainland China for trial. The legislation has since been suspended, but protests have continued with calls for sweeping democratic reforms in the former British colony and investigations into alleged abuse of force by police.

China's Hong Kong affairs office described the recent demonstrations as "near-terrorist acts" and repeated support for local authorities to severely punish those responsible.

During an event in Toronto on Wednesday, Freeland said Canada is "very aware" of the 300,000 Canadians currently in Hong Kong.

"We are very thoughtful about the situation," she said, adding that the department has been making "careful plans for all contingencies" for some time.

Freeland did not say what options are under consideration, but her office said in situations like this, the government consults with Canada's embassies and consulates, other countries, as well as the airlines and tour operators.

Freeland also repeated her plea for Canadians to pay attention to the government's travel advisories. Global Affairs Canada is now advising travellers to exercise a "high degree of caution" before heading to Hong Kong.

Hong Kong police have arrested more than 600 people since June for unlawful assembly, assaulting police officers and possessing weapons.

Conservative foreign affairs critic Erin O'Toole said the government must do more to stand up for human rights.

"The Liberals have been paralyzed by inaction in their diplomatic dispute with China for eight months and have been troublingly silent over the last few months in the face of pressures on Hong Kong from Beijing," he said in a statement to CBC.

"Canada has deep personal connections with Hong Kong through the 300,000 Canadian citizens who live there and because of the sacrifice of Canadians who died defending Hong Kong in World War II. It is time for the Liberals to unequivocally stand up for human rights, rule of law and respect for the one country, two systems promise made to Hong Kongers decades ago."