A total of 39 people were found socialising in illegal entertainment outlets in the latest police operation following the emergence of the KTV Covid-19 cluster last week.
In a statement yesterday, the police said they arrested three men, aged between 24 and 37, for supplying liquor without a licence.
The men are believed to be operators of the outlets in Selegie Road and Tagore Lane.
The other 36 people - 16 men and 20 women - are being investigated for not complying with safe distancing rules. They are aged between 20 and 38.
During the operation on Saturday, the police seized karaoke equipment, liquor bottles and beer cans from the outlets.
They said public entertainment and liquor are believed to have been provided at the outlets without a valid licence.
"Members of the public are advised to take the prevailing safe distancing measures seriously," the police added. "The police take a stern view of irresponsible behaviour relating to the flouting of safe distancing measures."
Those found guilty of supplying liquor and providing public entertainment without a valid licence may be fined up to $20,000 for each charge. Those convicted of breaching safe distancing measures may be jailed for up to six months, fined up to $10,000, or both.
The operation comes amid calls to crack down harder on the illicit nightlife sector after the KTV cluster emerged on July 12.
The cluster, which involves social hostesses who allegedly frequented KTV lounges and clubs, grew to more than 170 cases yesterday.
The latest operation is the third the police have conducted in the span of a week, involving the nightlife entertainment sector.
From last Tuesday to last Thursday, the police checked 27 KTVs that were operating as food and beverage establishments after Covid-19 curbs were put in place.
Officers checked a total of 281 people in the islandwide anti-crime operation, and arrested 29 women for offences under the Women's Charter, the Immigration Act and the Employment of Foreign Manpower Act.
Of these women, 10 are to be deported after they were found to be hostesses. Of the 27 outlets, 11 were also found to have likely breached safe management measures.
In another operation, the police arrested 20 women of various nationalities for their suspected involvement in vice-related activities within three pivoted KTVs in South Bridge Road, Selegie Road and Geylang Road.
The three KTVs are also being investigated for breaches of safe management measures.
Mr Joseph Ong, president of the Singapore Nightlife Business Association, told The Straits Times that the recent arrests show that there are still many illegal operators who have disguised themselves with legitimate frontages.
He said: "The nightlife business industry has been badly affected by these illegal operators, and people mistakenly associate them with legitimate nightlife businesses because they operate mainly at night.
"The authorities should take a very firm stance against all of these bad actors and not allow them to operate in any shape or form."