Almost 90 per cent of the new coronavirus cases announced yesterday were foreign workers living in dormitories.

They made up 654 of the latest daily high of 728 cases the Ministry of Health (MOH) confirmed as of noon yesterday, with two more large purpose-built dorms and three other factory converted dorms emerging as new clusters.

This takes the total number of foreign workers linked to dorms who have tested positive for Covid-19 to 2,689 - about 60 per cent of Singapore's current count of 4,427 cases.

Singapore's largest cluster, S11 Dormitory@Punggol, saw another 181 cases and now has 979 cases, comprising about one in five patients in the country.

MOH noted in its situation report that the prevalence of the disease among foreign workers living in dorms is much higher than work permit holders not living in dorms and among the general population.

Its data showed that about 0.83 per cent of the 323,000 living in dorms have so far been infected.

The corresponding figures are 0.03 per cent for the 664,000 work permit holders not living in dorms and 0.02 per cent for the 4.6 million citizens, permanent residents and other foreigners in Singapore.

The number of new cases among work permit holders outside dormitories has gone up from an average of nine cases per day in the week before to an average of 15 per day in the past week.

Compared with the average of 38 daily cases two weeks ago, the number of average daily community cases in the past week has remained fairly constant at 37.

MOH said the significant increase in cases among workers living in dorms is in line with its efforts to test and isolate infected workers.

About 19 per cent of the new cases announced yesterday are currently unlinked.

To increase the country's capacity to care for the rise in patients, several organisations are currently repurposing the Changi Exhibition Centre (CEC) into a temporary holding facility.

When ready, the 33,000 sq m space will be able to house up to about 2,800 patients who are recovering or who are in the early stages of the disease and showing only mild symptoms.

Senior Minister and Coordinating Minister for National Security Teo Chee Hean, who is advising the multi-ministry task force on tackling Covid-19 in the dorms, met the team repurposing the centre yesterday.

The CEC will be the third community isolation facility after the Singapore Expo and D'Resort NTUC.

Meanwhile, a third nursing home was hit by the virus yesterday, with an 89-year-old resident at Pacific Healthcare Nursing Home now warded in an isolation room at Ng Teng Fong General Hospital.

Affected areas in the Senja Road nursing home have been thoroughly cleaned and disinfected, and those who have had close contact with the resident will be quarantined, the Agency for Integrated Care said yesterday.

Two other nursing homes - Vanguard Healthcare's Woodlands Care Home, as well as Lee Ah Mooi Old Age Home - have previously reported cases.

As of noon yesterday, 31 more patients were discharged, bringing the number of patients who have fully recovered to 683.