HIS art now fetches millions, but another of Melbourne's dwindling stock of public works by street artist Banksy was drilled into oblivion this afternoon by unsuspecting construction workers in Prahran.

The shop on the corner of Izett and Greville Streets was being converted into a cafe as the image of a parachuting rat dangled in harm's way.

"It's like they used it as a bullseye", said Jacqui Vidal, who runs a studio across the road. "What they've done is punch a hole right through the brick, which was an image of a parachuting rat. And they've put two pipes right through."

However, Ms Vidal said the unwitting builder was not to blame.