Airlines risk being banned from transferring passengers at Hong Kong International Airport under stiffer punishments to be rolled out from July 1 after a fiasco in which people were stranded in transit for up to three months.

The Airport Authority Hong Kong on Tuesday unveiled the stiffer sanctions, which go beyond existing penalties such as fines, after it emerged over the weekend that more than a dozen transfer passengers had been trapped airside with nowhere to go for up to three months during sweeping global coronavirus-related border and travel restrictions.

“To avoid the recurrence of passengers being stranded at Hong Kong International Airport due to the mishandling of transit/transfer services by airlines, the Airport Authority has raised matters regarding the strengthening of flight management, immigration and quarantine for transit/transfer passengers,” the airport operator in a statement posted on its website.

Other new punishments would include passport and boarding pass checks immediately after disembarkment for a specific flight number, if the airline had on a previous flight brought in transit passengers who were not accepted by authorities because of travel restrictions.

“In case of serious violation, the transit/transfer service at Hong Kong for the flight of the same flight number may be suspended,” it warned.

The authority added that airlines would have to bear all the costs for passenger mishandling cases and would be responsible for sending those without valid boarding passes back to their airport of departure immediately.

Concerns had been raised after it was revealed that transit passengers have been stranded at the airport with no resolution to their plight in sight.

Some were stuck there because they shared a flight with passengers previously found to be infected with Covid-19 and thus were not allowed to take a connecting flight to mainland China.

All of the stranded passengers tested negative for the virus, but they were only checked after growing public concern. One case involved a Cathay Pacific passenger who arrived from Canada in late March but failed to take a connecting flight to Vietnam.

Some of those stranded remain at the airport while others were taken to a government quarantine camp.