The ministry said the "vast majority" of Friday's cases are foreign migrant workers living in dozens of crowded dormitories that emerged as hotbeds for transmission in late March

A summary published by the ministry on Thursday shows a cumulative 27,541 cases in dormitories, where over 300,000 mostly young male immigrants from across Asia reside while working in sectors such as security and construction.

Despite Singapore's miniscule size - a population of around 5.8 million that includes 1.4 million foreigners and crammed onto 724 square kilometres - it has confirmed more cases of Covid-19, the disease caused by the new coronavirus, than any country in East Asia outside China.

The Health Ministry attributed Singapore's relatively heavy caseload to "extensive testing in these premises," referring to the dormitories.

Only 13 of Thursday's 448 cases were designated as "community" - meaning among Singaporeans or others living outside the migrant worker dormitories. Friday's preliminary data suggested only four new cases involving Singaporeans.

With so-called community cases down to an average of 6.5 a day over the past two weeks, the government said on Tuesday that the lockdown it imposed on April 7 will be lifted in "a careful and calibrated manner" from June 1 as scheduled.

Australian Associated Press