COUNTERFEIT cash circulating in the Mackay region has been detected by a self-service checkout.

Mackay police Senior Constable Steve Smith said staff from a Mackay business contacted police after their supposed $50 note was rejected by one of the machines in recent days.

"Staff from a Mackay business attended a supermarket and when paying for their purchase in a self-service checkout, the $50 note presented for payment was not accepted,” he said.

"Suspicions were raised by (supermarket) staff when the note was handled by them. As a result, police were contacted.

"Almost exclusively, suspected counterfeit notes are being identified when they are handled in the Mackay police district as that's when the warning flags are raised. They clearly feel different to a normal and legitimate dollar note.”

Snr Const Smith said there's no suggestion the counterfeit note was deliberately used.

"There is however a need to remind local businesses that they should remain on guard when handling $50 notes in particular as our district has been exposed to them previously and there may very well continue to be some in circulation,” he said.\

If you suspect you've accidentally obtained counterfeit money get in touch with Mackay police.

Sen Const Smith said Mackay police have only come across fake $50 notes so far.

Mackay Police Station can be contacted by phoning 4968 3444.