Health Secretary Lo Chung-mau on Sunday said it would be unreasonable to expect quarantine-free travel to the mainland anytime soon, but the government still aims to make it easier for more people to cross the border.

On a TV programme, he said he understands that people have high expectations, but quarantine-free travel would require a drastic change in the country's anti-epidemic measures.

Lo said he hopes the quota for travellers and the supply of quarantine hotels in Shenzhen can be increased.

He added that Hong Kong should raise its PCR test standards, noting that some travellers tested negative for Covid-19 in Hong Kong but were later found to have the virus after they had travelled to the mainland.

"There was a period during which about 2.5 percent of travellers from Hong Kong tested positive for Covid-19 after crossing the border," he said.

"If we improve our PCR tests and meet our country's standards, so that all our travellers test negative after crossing the border, mainland authorities would naturally relax the regulations and more people would be able to travel there."

He added that he had discussed with the Innovation, Technology and Industry Bureau ways to improve the LeaveHomeSafe app to help prevent the spread of Covid-19.

Lo said residents who are subject to mandatory Covid tests should be ordered to avoid visiting high-risk venues such as restaurants.

He said authorities might take reference from the health code used on the mainland, where people are categorised into three groups according to their infection risks.