Authorities on Monday reminded operators of restaurants and other catering premises that they'll have to enforce tightened vaccine pass requirements from Tuesday, with most people now required to have had three Covid jabs.

The Food and Environmental Hygiene Department said it would continue to take "stringent enforcement action" if businesses flout the vaccine pass rules or other requirements, including limits on group gatherings and mandatory mask-wearing.

Under the latest phases, most people will have to have had three doses, or to have had their second dose no longer than three months ago. Separate rules apply for those who've recovered from Covid within six months and those granted medical exemption.

The department said that, between December 30 and Sunday, it initiated prosecutions against operators of 409 catering premises and two scheduled premises suspected of breaching requirements, and issued fixed penalty notices to 74 staff and customers.