Temperature screening before paid sex: This is a precaution that a Telegram group chat advertising sexual services has imposed on its clients.
Illegal sex work has persisted, with services advertised online, despite safe distancing measures being flouted under the rules of the circuit breaker.
In a police operation held earlier this month, 30 women were arrested for suspected involvement in vice-related activities.
A total of 19 men were fined after they were caught during the raids on various premises, including a hotel.
But not all sex workers are willing to take the risk.
Part-time sex worker Serena (not her real name) said that she, like many local sex workers, has stopped offering services during the circuit breaker period.
"We are afraid to do it because there are fines and everything," the 35-year-old told The Straits Times over the phone.
Persons engaging in sexual services may be issued notices of composition under the Covid-19 (Temporary Measures) (Control Order) Regulations 2020 for failing to comply with safe distancing measures, said the police.
Not all sex workers and their clients are paying heed, as evident from the websites and chat groups still advertising and posting customer reviews of paid sex.
Some platforms claimed to be taking precautions, with one saying that its sex workers had not recently travelled to the Chinese city of Wuhan, even though the first epicentre of the pandemic has brought the virus under control.
One private Telegram group chat is offering pornographic photos and videos of a sex worker for a one-time fee of $68, while another was earlier reported by Chinese-language newspaper Shin Min Daily News to be offering pornographic content for monthly or quarterly subscriptions.
Number of foreign women arrested for online vice in 2018, almost double the number in 2015.
In the meantime, some sex workers are finding it hard to make ends meet.
Project X, a non-profit organisation which looks out for the welfare and rights of sex workers, said it has been approached by over 100 sex workers for help since the start of the circuit breaker on April 7.
Half of them are migrant workers while the rest are locals, said Project X spokesman Vanessa Ho.
"The biggest issue for a lot of them is that they cannot afford to pay their rent and were on the verge of being evicted," she said.
Ms Ho said the organisation has negotiated with their landlords to delay or stagger rental payments.
She added that Project X has also introduced a new initiative, the Emergency Safety Net Programme, to assist sex workers during this period - either through cash payouts or by including them in its food distribution scheme.
A report by the National University of Singapore's Saw Swee Hock School of Public Health, published last year, estimated there are 4,200 female sex workers here.
Police figures released last year show that 1,417 foreign women were arrested for online vice in 2018 - almost double the number in 2015.
Vice activities have been observed by the police to be increasingly moving into residential estates, with online platforms used to advertise and solicit clients.