Victoria's gambling regulator banned Tabcorp from taking bets on the recent UFC cage fighting event in Melbourne, amid warnings by law enforcement agencies that the sport was vulnerable to corruption and money laundering by organised criminals.

It was the first time the Victorian Commission for Gambling and Liquor Regulation had refused an official request to allow punting on a sports event and delivered a strong rebuke to the UFC, which ranks as one of the world's most valuable and powerful sporting franchises.

Challenger Holly Holm knocks down champ Ronda Rousey in UFC 193 at Etihad Stadium. Credit:Darrian Traynor

A commission spokeswoman confirmed it had prevented Tabcorp from taking bets on any fights at UFC 193 in November, which attracted a record crowd of 56,000 at Etihad Stadium and a massive global television audience.

The event featured the much-anticipated title bout between world champ Ronda Rousey and Holly Holm, which saw Holm cause a stunning upset with a second-round knockout.