SINGAPORE - A Raffles Girls' School student who was last in school on Dec 23 was among the five community cases announced on Thursday (Dec 31).

The 14-year-old permanent resident was one of two family members of Case 58,810, a permanent resident who works as a marine surveyor at Lloyd's Register Singapore, said the Ministry of Health (MOH) on Thursday.

The other family member is a 46-year-old permanent resident who works as a freelance florist at her place of residence at Ghim Moh Road.

Both of them live in the same household and had been placed on home quarantine on Dec 30.

The third community case is a 55-year-old Singaporean man who worked as a harbour pilot at PSA Marine in West Coast Ferry Road.

He boards vessels as part of his work to navigate them through congested waters, said MOH.

The man was asymptomatic and had been detected via the ministry's rostered routine testing of workers in the construction, marine and process sectors.

MOH added that on Dec 13, the man had visited Parkway Parade with seven other individuals and was known to visit his relatives who stayed near his residence at Marine Crescent.

Investigations are ongoing to assess if there was any breach of safe management measures, the ministry said.

The other two new community cases are a 79-year-old Singaporean woman who is a retiree and a 50-year-old male Singaporean who is currently unemployed.

Both of them are relatives of the 55-year-old man who stays at Marine Crescent.

MOH added that all the identified close contacts of the cases, including their family members and co-workers, have been isolated and placed on quarantine.

They will all be tested at the start and end of their quarantine period so that the ministry can detect asymptomatic cases.

The Government has also said that it is reviewing precautionary measures for workers in the marine sector.

MOH will commence special testing operations to test people who had boarded the ships that Cases 58,810 and 58,817 recently worked on.

It will also test harbour pilots, marine surveyors and ship repair workers in the coming days, regardless of their rostered routine testing schedule, to determine if they have the virus.

"In view of the recent cases involving the marine sector, we will review the need to tighten our precautionary measures for these workers," said the ministry.

The review of precautionary measures for workers in the marine sector comes after the authorities tightened safety measures for airline crew, following news that a Singapore Airlines cabin crew member and a pilot had tested positive for Covid-19.

The five cases in the community announced on Thursday is the highest daily community figure since Aug 30, when there were eight cases.

There were also 25 new imported coronavirus cases confirmed on Thursday. This means there were 30 new cases on Thursday, the highest daily total since Sept 21, when there were 31 cases.

Thursday's new cases take Singapore's total to 58,599.

The 25 were placed on stay-home notices or isolated on arrival in Singapore, said MOH.

Among them, two are Singaporeans and three are permanent residents.

There are also two work pass holders, 14 work permit holders of which nine are foreign domestic workers, one dependant's pass holder, one long-term visit pass holder, one short-term visit pass holder and one special pass holder.

The imported cases came from various countries including the United Kingdom, Indonesia and India.

Geylang Serai Malay Market and Food Centre, Kampong Glam Cafe in Bussorah Street and New Hawa Restaurant in Changi Road were among places visited by Covid-19 patients while they were still infectious, said MOH.

Overall, the number of new cases in the community has increased to seven, with a total of three cases in the past week who are currently unlinked.

A total of 57 patients remain in hospital while 64 are recuperating in community facilities. One patient is in critical condition in the intensive care unit.

"The recent community cases are a stark reminder that we cannot afford to let our guard down, especially during this festive period when there are increased social interactions," said MOH.

"Let us work together to avoid an uncontrolled resurgence of cases which could slow or even reverse our progress," it added.