Hong Kong on Thursday shortened the mandatory quarantine for international travellers from three weeks to two, even as the city struggles to contain virus outbreaks involving Omicron and Delta variants.

Like mainland China, Hong Kong is one of the few places left in the world still pursuing a "zero-Covid" strategy that has largely kept the virus at bay but left the finance hub internationally isolated.

The emergence of the highly transmissible Omicron variant saw the city increase its travel restrictions in December -- slamming borders shut to arrivals from eight countries and banning transit passengers from more than 150 destinations.

But Hong Kong leader Carrie Lam on Thursday said beginning February 5, the three-week mandatory quarantine period for all arrivals -- some of the longest isolation measures in the world -- will be reduced to two weeks.

"All arrivals to Hong Kong will undergo 14 days mandatory quarantine in designated hotels and seven days of self-monitoring at home," she said.

Arrivals will be able to leave their homes during the final days but are required to take a Covid test at least twice, she added.

Hong Kong is one of the few places left in the world still pursuing a 'zero-Covid' strategy
Hong Kong is one of the few places left in the world still pursuing a 'zero-Covid' strategy AFP / Peter PARKS

However, social distancing measures across the city -- like the ban on restaurant dining after 6 pm -- will be extended for two more weeks, while schools will still be suspended.

The ban on people arriving from eight countries -- Australia, Canada, France, India, Pakistan, the Philippines, the United Kingdom and the United States -- will continue for another two weeks, to February 18.

The extension come as Hong Kong prepares for the Lunar New Year, a usually raucous affair during which boisterous street fairs see lion dance performances and families gather for meals.

"But considering the dire Covid situation, I have to appeal to all residents to stay at home, reduce cross-family gatherings and join hands to fight the virus," Lam said.

Hong Kong's mandatory three-week quarantine is one of the longest in the world. It has been subject to a barrage of complaints from the international business community, with firms saying the policy deters talent from entering transport and logistics hub.

Lam on Thursday said the policy change was "purely based on science", due to Omicron's shorter incubation period.

Hong Kong on Thursday recorded 164 confirmed infections -- the highest daily figure since the pandemic began -- though only 116 were local cases.