The regulator requested Australian internet service providers (ISPs) block Reef Reels, Royal Reels, Ricky Casino, Slots Gallery and Slotastic sites.
They were all found to be operating in breach of the Interactive Gambling Act 2001.
The ACMA made its first blocking request in November 2019 and 803 illegal and affiliate websites are currently blocked.
Additionally, over 200 illegal services have pulled out of Australia since ACMA began enforcing illegal offshore gambling rules in 2017.
“The ACMA is reminding consumers that even if a service looks legitimate, it is unlikely to have important customer protections,” the regulator stated. “This means Australians who use illegal gambling services risk losing their money. You can check if a wagering service is licensed to operate in Australia on our register.”
A total of 67 licensed TABs, corporate bookmakers and betting exchanges are listed on the register.