BANGKOK: A Bangkok clinic that has drawn 100 men a month to its penis whitening service has caused a stir in Thailand, with social media users both baffled and alarmed by the phallic fad.

The Lelux Hospital, renowned for its body whitening expertise in a country obsessed with skin colour, began offering the unconventional treatment six months ago after a male customer complained of "dark parts" on his groin.

"These days a lot of people are asking about it. We get around 100 clients a month, three to four clients a day," Bunthita Wattanasiri, a manager for the Skin and Laser department at Lelux Hospital told AFP.

The procedure, which uses laser whitening, got wide play on Thai television and social media on Thursday (Jan 4) after the hospital released images of a man undergoing the treatment.

"We have to be careful because it's a sensitive part of the body," Bunthita said, adding most clients were aged between 22 and 55-years-old with many from Thailand's LGBT community.

She said they use a very small laser.