Pink diamond ring, worth $577k, stolen in Sydney

A diamond ring worth more than half a million dollars has been stolen at a Sydney auction centre.

A supplied image of the unique pink diamond ring worth more than half a million dollars that was stolen from an auction centre in Alexandria, Sydney. (AAP/Police Media)

The unique pink argyle and white diamond ring, valued at $577,000, was nicked from a display counter at the centre in Alexandria, in Sydney's inner-east, between 12.30pm and 1.25pm on Saturday.

Each of the diamonds in the ring is laser inscribed with a serial number.

An attendant at the auction discovered the ring missing and contacted police.

Police are appealing for any witnesses to come forward.

Finding the ring might prove to be a challenge as about 100 people walked through the auction centre around the time it was stolen.