The Departments of Labour and Immigration looked into the allegations by the Indian men, who claimed they were poorly treated by Jordanian Yousef Bader at the Sky Liquor, Symonds Liquor and Civic City Convenience Stores.
Sandeep Bhardwaj, 23, said he was employed for 10 months at Civic City, working nine-hour shifts seven days a week, and was paid $300 a week.
One News has revealed that a series of Chinese food outlets are paying staff $8 an hour.
The Labour Party's spokeswoman for labour and immigration, Darien Fenton, said an urgent investigation was needed.
"When there was exploitation and under-payment of minimum wage for foreign fishing crew the Government conducted a ministerial inquiry because of the stain on our international reputation.
"This kind of treatment of workers ... is an indictment on our reputation as a country that has signed up to minimum rights for all workers."