A passenger on the flight from Chengdu wrote in an online post that flight attendants complained amongst themselves about passengers in English and Cantonese.

China's state media meanwhile criticises the airline for 'worshipping foreigners'.

The city tightened quarantine rules for air crew after the outbreak, leading the airline to cancel most of its planned passenger and cargo flights in January.

Cathay said five of its aircrew had tested positive following their return to Hong Kong from duty, and investigation into the cases had indicated a serious breach of protocols by some of those individuals.

Cathay Pacific is especially vulnerable because it has no domestic market to fall back on and is based in an international finance hub that has embraced mainland China's 'zero-Covid' plan.

Also, Hong Kong's Cathay Pacific has joined the ranks of international airlines who now require all aircrew to be fully vaccinated against Covid-19.

Many countries are introducing strict testing and quarantine rules for international flight crews.

Neither destination has a domestic air travel market, so their airlines are totally reliant on international flights.