A group of diners at a posh restaurant in Melbourne who scarpered without paying the bill have been tracked down using Facebook.

The five young diners pretended to head outside to smoke but didn't come back leaving the owner of the Seagrass on Melbourne's Southbank with a $520 ($340) bill.

However, owner Peter Leary remembered that one of the group had asked about a former waitress of his and so he contacted her. She then suggested that Leary check through her Facebook contacts.

Says Leary: "We searched a few names and there in front of us his face [one of the diners] came up.

"He was pictured with his girlfriend who was the only girl in the group. We also knew where he worked, at a nearby restaurant, which was handy. It'd been clear they were in the trade".

Leary contacted the owner of the other restaurant and, within hours, the diner, who had, with his friends munched down oysters, trout and red emperor washed down with some expensive wines, returned to pay the bill.

Both this man and his girlfriend have now been sacked.

"On this occasion I guess you could say that being on Facebook backfired for them", concluded Leary.