Hong Kong's government said on Monday that it would shorten the quarantine period for vaccinated people arriving in the city to seven days from 14 days provided travellers show sufficient antibodies against the coronavirus.

Leader Carrie Lam, who was speaking at a press briefing, said the new measures were only applicable to people who have logged 14 days following their second vaccination dose. The rule change is due to take effect from the end of the month, she said.

The Chinese-ruled city has some of the toughest quarantine rules globally with residents mandated to stay for up to 21 days in hotels after arriving.

The move to reduce the quarantine duration comes as the government tries to incentivise more of its 7.5 million population to get COVID-19 vaccinations. So far only around 17% of residents have been fully vaccinated since the scheme started in February.

For those arriving from countries deemed "very high risk" the quarantine period remains unchanged at 21 days.

Health Secretary Sophia Chan, speaking at the same press conference, said some social distancing measures including increasing capacity at restaurants and bars would be eased from June 24 for vaccinated residents.

Hong Kong authorities have over the past month piled pressure on businesses and financial institutions to encourage vaccinations and urged them to grant employees a day off for each jab.

Many corporates have unveiled incentives and rewards for vaccinations while some companies and private clubs have threatened to deny pay rises or lay off workers if staff do not get jabbed.

The former British colony has largely controlled the virus with around 11,800 infections and 210 deaths, with the majority of residents choosing to delay vaccinations.

There remains a surplus of unused vaccines and some are about to expire, the government said.