Beijing has hit back at Ottawa over a mid-air encounter between a Canadian aircraft and PLA fighter jets over the South China Sea late last month, describing the Canadian action as provocative.

Chinese defence ministry spokesman Zhang Xiaogang said on Saturday that a Canadian helicopter conducted flights of "unknown intent" to approach the airspace around the Paracel Islands, known in China as the Xisha.

Zhang said the People's Liberation Army's naval and air forces had identified the Canadian helicopter and repeatedly issued warnings, but it "refused to respond" and "took provocative actions such as flying at ultra-low altitude".

The Canadian flights represented "malicious and provocative actions with ulterior motives", Zhang said.

Beijing's response came after Ottawa accused the Chinese air force of unsafe behaviour over international waters in the South China Sea on October 29.

Canadian Defence Minister Bill Blair said on Friday that the Chinese aircraft engaged in "significantly unsafe" action, Reuters reported.

The Canadian Armed Forces said their CH-148 Cyclone helicopter was conducting routine exercises in the South China Sea when it was intercepted by two PLA J-11 fighter jets.

It said that one jet conducted a pass over the Canadian helicopter "with little separation, causing the helicopter to experience turbulence". Later that day, another J-11 fighter aircraft "launched flares directly in front of" the same Canadian helicopter.

"All interactions took place in international airspace, well outside any claimed territorial seas and associated airspace," the Canadian Armed Forces said, noting that the Canadian aircraft was "subject to multiple close-proximity manoeuvres" by the Chinese fighter jet that "put the safety of all personnel involved at unnecessary risk".

"Canada expects that any intercepts of our aircraft be conducted in a safe and professional manner. The Canadian Armed Forces will continue to contribute to a more secure and stable Indo-Pacific, including through the deployment of Royal Canadian Air Force aircraft."

It was the second time in two weeks that Canada had accused PLA jets of unsafe behaviour.

In mid-October, Blair said a Chinese aircraft had buzzed a Canadian surveillance plane taking part in a United Nations operation in the East China Sea, while Beijing hit back at what it said were attempts to "cause trouble and provocation at China's doorstep".

Beijing claims most of the South China Sea through what it calls its historical "nine-dash line". The Paracel Islands consist of about 130 small coral islands and reefs covering an area of 7.75 sq km (3 square miles) and also claimed by Vietnam and Taiwan.

Canada "violated China's domestic law and relevant international law and endangered China's sovereignty and security" in the October 29 encounter, the Chinese defence ministry said

"We urge the Canadian side not to ignore facts, to stop exaggerating and speculating, and to strictly restrain the actions of frontline air and sea forces to prevent accidents at sea and in the air," Zhang said.

"The Chinese military is on high alert at all times, resolutely defending national sovereignty, security and maritime rights and interests, and resolutely maintaining peace and stability in the South China Sea."