A well-dressed thief used stolen credit cards to embark on a high-end shopping spree at designer stores in Melbourne worth nearly $240,000.

The man, who wore a white collared shirt and dark suit jacket, began his luxury shopping jaunt on the "Paris end" of Collins Street, with a wallet full of credit cards believed to have been stolen from post boxes in Sydney's western suburbs.

The man police wish to speak to Credit:Crime Stoppers.

He first visited the Monards Swiss watch store on Collins Street, where he spent $115,000 in one transaction.

Next on his hit list was Cartier, where he bought $10,000 worth of jewellery.