The notes are of good enough quality but do not have good watermarks.
The bogus notes first came to light when a local taxi-driver went to pay his car tax and found a fake €50 in his wallet.
“I had a number of €50 notes in my wallet to pay my tax and I noticed this one did not look good.
“I took it to the Garda station and they told me it was fake,” he said.
A Garda spokesman said there could be a number of the notes in circulation.
“It was a busy weekend in the town and people might have been in a rush and did not check these notes.
“We believe there could be a few in circulation.
“WE are asking the general public and business owners to check when they receive €50 notes. If they suspect there is anything wrong with them, then they should contact us immediately,” he said.