The source said that it is expected that improvements to the health code can be completed within this year.

As for its applicability, the source said the app may apply to everyone but it is too early to say.

"In order to make it on par with the mainland, the frequency of Covid-19 tests needs to be increased too, regardless of whether people are vaccinated or not," the source said.

Carrie Lam says the government has to try its best to control the pandemic so that normal cross-boundary flow of people can be resumed as early as possible.

Last month, the Chief Secretary for Administration led a delegation of the HKSAR government to attend a meeting on anti-epidemic work with relevant authorities in the mainland. During the meeting, the two sides explored in detail matters relating to the gradual and orderly resumption of quarantine-free travel between the two places and assessed the possible risks after resumption of quarantine-free travel.

The two sides will further study the related details and strive to hold a second meeting as soon as possible, Lam said.

“To resume cross-boundary travel, the support of the public is vital. If you, your family or friends have not got a jab yet, please do not hesitate anymore and get vaccinated as soon as possible to prevent yourself and your family from infection, and help create favourable conditions for cross-boundary travel,” she said.