Health Secretary Lo Chung-mau on Saturday said he was disappointed by seven doctors suspected of issuing Covid vaccine exemption certificates without conducting proper medical consultations, adding that the medical sector was "humiliated" by them.

Speaking after an RTHK programme, Lo said 2,042 out of some 20,000 people who were earlier issued the certificates by the seven doctors have now been vaccinated, saying that proved they had no reason to be exempted from inoculation.

"There are seven doctors suspected of professional misconduct and even criminal offences. As a doctor myself, I am not only disappointed but feel that is a great humiliation to the medical sector. The medical sector in Hong Kong has always been deemed very professional," he said.

Meanwhile, he said the vaccine pass arrangement will stay, saying the Covid situation has eased because people have been inoculated against the virus, and the vaccine pass policy is enabling society to return to normal.

Asked why the government has not moved from the current 0+3 policy to 0+0 - effectively scrapping the three-day medical surveillance for inbound travellers - the minister said they need to monitor Covid-19 sub-variants.

"As arrival figures have increased, there have been more [imported] cases daily, which take up a larger proportion of the total number of infections. More importantly, most of the new sub-variant cases we see now were detected through screening of arrivals, so we think the policy now is effective," he explained.

Separately, Lo said authorities will consult the healthcare sector as they look into a Policy Address proposal to require medical professionals to work in public hospitals for a period before going private.

Lo said lengthy training - subsidised by taxpayers' money - is needed to train specialist doctors, and people should think if these workers should serve society before they can join the private sector.

"Who is going to take on the work of those who left? Those staying will have a tougher time as they will be under more stress... I hope our colleagues will not think that leaving [the public sector] for the private sector is something they should do," he said.

The official added the Hospital Authority has created more opportunities for career advancement and will also review the remuneration package regularly to retain talent.