Thailand's public health ministry has issued a warning over a new and bizarre trend of penis whitening, which has been linked to the country's assocation of paleness with success.

Skin whitening is popular across south east asia as darker skin is associated with outdoor labour and being poorer, with a wide range of bleaching products on the market.

In Thailand the phallic fad has unexpectedly extended to men who believe a paler penis and groin area looks more attractive.

But health officials have urged people to rethink undergoing the procedure, which can lead to scarring, inflammation and "nasty looking spots."

"Penis laser whitening is not necessary, wastes money and may give more negative effects than positive ones," the health ministry's Dr Thongchai Keeratihuttayakorn said in a statement.

The warning was issued after video footage of a clinic carrying out the unusual procedure went viral online.

Internet users were shocked and amused in equal measure by the video, which has been shared more than 19,000 times, with one of them commenting under the clip: "It can be used as a torch light. Let it shine!"