A police alert, which went out on Friday, said that after befriending the victims, the foreign men would claim they are coming here to visit the woman or to ask for her hand in marriage.
On the day he is supposed to arrive, he will call her to say that he has been detained by the Singapore authorities for carrying excessive cash.
The men will then beg for a transfer of a sum of money to a foreign bank account to secure their release. Once the cash is in, all contact will cease.
Police investigations have revealed that there were no such persons on any flight, vessel or bus entering Singapore that day.
Those with information on such scams should call the police hotline: 1800-255 0000, or 999 if urgent police action is required.