Southern Police have advised of fake $50 notes circulating in the South Island with one such note being handed into Queenstown Police.

An image of the note posted on the Southern District Police Facebook page explains how to spot the difference between a fake note and real cold hard cash.

"We have had recent reports of counterfeit $50 bank notes being circulated in the South Island.

"There are now incidents of these being used in Queenstown.

"[This] is a photo of one of the notes handed in to Queenstown Police which highlights some security flaws."

For more information on how to spot a counterfeit note, please visit this website.