Minister Meutia Fardia Hatta Swasono reacted angrily to reports of locks being fitted to the trousers of female staff in a small town in Indonesia, where massage parlours are often used as a front for prostitution.

"It's not the right way to prevent promiscuity. It insults women as if they are the ones in the wrong," Swasono, the Minister for Women's Empowerment, told the Jakarta Post.

The daily said authorities in Batu in East Java had ordered masseuses to wear the padlocks to protect the resort town's reputation.

But the massage parlour owner who first introduced the locks said he did so for the good of his workers.

"You know well how naughty some clients can be," said Frangki Setiawan, owner of the Dogado massage parlour in Batu.

"It is a move taken purely in the interest of the working safety of my staff."

Most of the town's 20 massage parlours have now adopted the practice after local police encouraged them to do so, Batu spokesman Hidayat said.

The Jakarta Post said the capital's tourism authorities were considering introducing the practice to improve thereputation of massage parlours in the city, which has a large but technically illegal sex industry.