A massage parlour in Petaling Jaya has been found offering free sex services to its loyal customers with every nine consecutive visits.

The ploy, which has been used by the operator for the past three months, was however busted last night when police stormed the premise in Sunway Mentari.

During the 9pm raid, nine Vietnamese women, aged between 18 and 28, who were suspected to be working as prostitutes were nabbed.

Also detained were nine men, including four locals believed to be the premise caretakers.

Stamp cards, used to redeem the free sex service, and condoms, found hidden in a microwave, were also seized.

Initial investigation showed the women had abused their social visit passes while two of them had been booked for a similar offence.

All those detained were brought to Petaling Jaya police district headquarters for further action.