SINGAPORE - While there have been recent Covid-19 cases in the community and the foreign worker dormitories, these figures should be put into perspective, said Transport Minister Ong Ye Kung on Monday (April 26).

He cited how four of the five community cases announced on Saturday were crew members working on a bunker tanker. "It's not a community case in the sense that they are running around the community. They were on a specific ship confined to our port area," he said.

On the 19 workers at Westlite Woodlands dormitory who tested positive for Covid-19 last week, the minister noted that there have no new cases in the past few days. "So that is a source of comfort that, hopefully, those dorm cases do not extend beyond that."

So for now, the conditions are currently right for the air travel bubble between Singapore and Hong Kong to take off on May 26 if the situation remains stable in the next month, Mr Ong said.

He was responding to a question about whether it was a good time to proceed with the Singapore-Hong Kong air travel bubble during an interview he gave at the Ministry of Transport.

The minister noted that the community cases who worked on a bunker tanker were classified as such as they had been operating in Singapore's port area.

"Bunker tankers are like petrol kiosks floating around our port refuelling different vessels coming into our port," he said.

"So there was a case on this vessel and all the ship crew, they were tested, and it was shown that four more on the same ship were positive. But throughout this period, the entire crew was on the ship. They've never gone into our community."

The Westlite Woodlands dormitory cluster was detected after a 35-year-old Bangladeshi worker tested positive for Covid-19 during regular testing for workers.

A roommate of his, who was deemed to be a close contact, tested positive for Covid-19 while in quarantine.

Seventeen other workers who had previously recovered from the virus were subsequently found to be Covid-19-positive as well.

The health authorities are currently investigating the cases to assess if they are reinfections or if they were still shedding the virus from their earlier infection.

Mr Ong noted that the first case was identified due to the "robust surveillance system" in the dormitories.

More than 30,000 Covid-19 tests are carried out daily in Singapore, with over 20,000 of these tests in the dorms, he said.

Westlite Woodlands dormitory was locked down immediately, with Covid-19 tests conducted on 3,000 residents, he added.

Asked why foreign worker dormitory Covid-19 cases are excluded from the case count that would determine whether the Singapore-Hong Kong air travel bubble is suspended, Mr Ong said this was because the risk profile of individual cases moving around in the community is much higher than infected patients in dormitories.

"It's a different environment - you can lock down the dorm... (but) you can't lock down Toa Payoh, you can't lock down Ang Mo Kio," he said.

"Someone in the community can circulate the virus and the chances of transmission are higher."

Mr Ong cautioned that Singapore will have to keep its guard up to avoid a repeat of last year's surge in Covid-19 cases in the dormitories.

He noted that workers are still unable to move around like they could before, and they get tested regularly for the virus.

In addition, the National Environment Agency is also doing wastewater testing to monitor the viral loads in dormitories.

"All these surveillance systems put us in a very different position compared with last year, when we had the dorm cases," he said.