The National Reserve Bank of Tonga is warning consumers of illegal 20 pa'anga notes being circulated.
The notes have been cut and joined together with clear tape.
The notes are shorter than genuine ones by 7-millimetres with different serial numbers on the sides.
The Board of the National Reserve Bank has granted a 5-day amnesty period starting from Monday to return any impaired notes for inspection.
However, any remaining notes which haven't been surrendered by 4 o'clock next Friday, will be deemed void.