Fake $100 notes are being passed at restaurants, pubs and shops across Melbourne as a counterfeiting ring has begun flooding the city with high-quality forged bills.

The influx of forged currency comes as the federal government considers a proposal to permanently remove the $100 note from circulation because of its popularity with organised crime syndicates, drug traffickers and tax cheats using the black economy.

In December 2016, Financial Services Minister Kelly O'Dwyer established a special task force to investigate the cash economy following a surge in the number of $100 notes in circulation detected by the Reserve Bank of Australia.

The new fake $100 bills are considered to be of a high-quality with only one major flaw - each has the same serial number: "AI 13933231".