BUSINESSES on the Darling and Western Downs have been targeted by counterfeiters, with several businesses across the region discovering they had been paid with fake tender.

Sergeant Graeme Frost of the Goondiwindi Police said a number of businesses in the area had been duped.

"The fake notes weren't discovered until the businesses had deposited their takings to the bank," he said.

"These notes are extremely well done and very difficult to spot and were only noticed by the banks."

Sgt Frost said the notes were mostly of the $50 denomination.

"It's likely they were passed off by someone traveling through town," he said.

"This is due to the nature of the businesses where the bills were passed, for example, a motel, retail stores etc.

"We don't have any leads at the moment, because of the period of time over which they were passed.

"It could have been any time between Christmas Eve to this week."

Detectives from the Goondiwindi Criminal Investigation Branch have warning local businesses and members of the community to remain vigilant.

Officers are investigating several incidents where counterfeit $50 notes have been used to purchase goods in townships including Miles and Oakey.

The offences occurred in a range of different retail and service businesses.

Sgt Frost urged all business owners and customer service employees to be mindful of people presenting large value notes for low value purchases.

"This is a timely reminder for all customer service employees to check the quality of all $50 and $100 notes before giving change to a customer," he said.

"Advice on how to identify counterfeit notes is available through the Reserve Bank of Australia website, but you should check notes for the security features including the coat of arms watermark, the clear plastic window is part of the note and not stuck on, and the Southern Cross stars look genuine and do not scratch off with moderate rubbing."

More information on detecting counterfeit notes can be viewed on the Reserve Bank of Australia website: http://banknotes.rba.gov.au/assets/pdf/counterfeit-detection-guide.pdf.

Anyone who may have any information concerning the manufacturing or distribution of these notes is urged to contact Crime Stoppers.

Anyone with information which could assist with this matter should contact Crime Stoppers anonymously via 1800 333 000 or crimestoppers.com.au 24hrs a day.

Crime Stoppers is a registered charity and community volunteer organisation working in partnership with the Queensland Police Service.

For all non-urgent police reporting or general police inquiries contact Policelink on 131 444 or Policelink.qld.gov.au 24hrs a day.