Four women and a man, between 40 and 52 years of age, were arrested following a raid by police at an illegal gambling den on Tuesday.
The police also confiscated three electronic mahjong tables and about $565 from the rented private apartment unit in Geylang, said the police in a statement on Wednesday.
Investigations are ongoing against the 43-year-old man, who allegedly ran the operation, The women are believed to be his patrons.
Any person who lets or helps a place be used for gambling will be fined between $5,000 and $50,000 plus up to 3 years' jail, while patrons will be fined up to $5,000 and/or up to 6 months in jail, if convicted.
Commander of Bedok Police Division, Deputy Assistant Commissioner of Police How Kwang Hwee, reminded home owners that they are responsible for ensuring their premises are not used for illegal activities.