Thirteen women were arrested for offering sexual services in residential units in Sembawang and Sengkang this month, the police said in a statement yesterday.
The women, aged between 22 and 49, had been advertising their services on websites and were operating in residential areas.
They were arrested under the Women's Charter for their suspected involvement in vice-related activities. The arrests were part of anti-vice operations by the Ang Mo Kio Police Division this month.
A 14th woman, who is 31, was arrested for working without a valid work permit.
The police also seized cash amounting to $1,970 and mobile phones.
They will be investigating the owners of the homes that the women had been using.
Anyone who is convicted of the offence of being the tenant, lessee or occupier or person in charge of a brothel can be jailed for up to five years and/or fined up to $10,000.
The penalties are the same for those found guilty of keeping, managing or assisting in the management of a brothel.
Additionally, anyone who is convicted of the offence of knowingly living wholly or in part on the earnings of a prostitute - such as receiving rental earnings from the prostitute - can be jailed for up to five years and fined up to $10,000.
The police said in the statement that they would spare no effort in clamping down on online vice activities, especially those operating in the heartland.
They also advised home owners to be diligent in ensuring that tenants do not carry out vice activities in their units.