A government adviser on the pandemic, David Hui, said on Sunday that Hong Kong could relax entry requirements again if Covid cases continue to fall and the healthcare system can cope.

He was speaking a day after the Secretary for Health, Lo Chung-mau, said the government is actively considering scrapping hotel quarantine.

Currently, arrivals to the SAR are required to spend three nights in a designated hotel and then monitor their health for the next four days, a so-called "three plus four" arrangement.

Speaking on a television programme, Hui said it's likely that the government will go for a "zero plus seven" policy first, noting that most imported cases were picked up during day four to seven of arrivals.

"The government may be cautious at first and adopt a 'zero plus seven' policy, but if there's no rebound in the community, it may be possible to cut back further on medical surveillance," the Chinese University professor of respiratory medicine said.

He also suggested the government could consider lifting the PCR test requirement for arrivals, since most have already been double jabbed and have to be tested on arrival.

But Hui urged the administration to do more to boost the vaccination rate among the elderly by providing them with incentives such as cash or e-vouchers, noting that many elderly patients have become seriously ill or even died after catching Covid.