Police are trying to catch a man who used a fishing rod to steal a Versace necklace off a mannequin through a shop window in Melbourne's CBD.

Key points: The man chipped a hole in the glass, then used two fishing rods to land his catch

The man chipped a hole in the glass, then used two fishing rods to land his catch The shop's owner said he was shocked by the "outrageous and courageous" crime

The shop's owner said he was shocked by the "outrageous and courageous" crime Anyone with information is urged to contact Crime Stoppers

The man spent almost three hours trying to hook the $800 costume jewellery off the dummy's neck, after breaking a hole in the window of high-end fashion boutique lestyle in Little Collins Street.

Police said the thief used two different-sized rods before eventually reeling in the Medusa medallion necklace just after 2:00am on Monday February 24.

Lestyle owner Steven Adigrati said the man chipped a hole in the glass without setting off the alarm.

"It's pretty outrageous and courageous," he said.

"To think he went back once, then twice, with a fishing rod and a hook, to make a little hole in the window then capture that necklace, I was pretty shocked."

lestyle on Little Collins Street has boarded up the window broken by the thief who stole the necklace. ( ABC News: Jean Edwards )

The stolen Versace necklace is worth $799. ( ABC News: Jean Edwards )

Mr Adigrati said the thief may not have realised the necklace was relatively inexpensive.

"This particular necklace looks a lot more expensive than what it is, so obviously the temptation was there: gold, bright, iconic Medusa head, so that would have been the temptation," he said.

Police have released CCTV footage of the man poking the rod through the window and pacing outside the shop.

Police have released CCTV footage of the man. ( Supplied: Victoria Police )

Detective Senior Constable Bede Whitty said the thief was well organised.

"It's fairly blatant and it's quite bold as well. I've not seen someone use a fishing rod to commit a burglary in the past," he said.

The man is described as Caucasian in appearance, aged between 40 and 50, about 180cm tall, with short, fair receding hair.

He was wearing a blue Lonsdale jumper and grey tracksuit pants.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.