In a six-minute video clipping posted on the Internet, the girl could be seen performing oral sex on a man on the upper deck of a bus as it rides across Hong Kong island with a few other passengers on board.

The video, which appeared to have been shot with a camera phone held by the man, has been circulated on the Internet under the heading “Kikimushroom do things on bus”.

The video also carried a description with it, and it has been posted on a number of popular Internet forums.

“Pay 200 dollars and get this service from a 17-year-old Hong Kong student. She wants to buy Gucci bag,” the Age quoted it as stating.

In the video, the man is heard describing the act the girl was performing, and he told viewers that her services were available “for a price”.

The girl, who was aware of the camera being trained on her, stared into it and commented on the “peaceful surroundings” outside the bus, as two other passengers sat in front of them unaware of what was going on.

Hong Kong police were investigating whether the video is linked to a trend called “compensated dating” - a euphemism for paid sex with young students - believed to have spread to Hong Kong from Japan.