Mandeep Singh pleaded guilty in the Dandenong Magistrates' Court on Thursday to one charge of fraudulently obtaining payments.
He was convicted and fined $1200 and ordered to pay costs of $1742.
The court heard Singh injured his ankle and back in a fall while working for Pacific Meat Sales.
He ceased work in September 2016 and received weekly workers' compensation payments.
An investigation later found Singh then started his own business as a courier driver, earning more than $26,000 until the fraud was uncovered in August 2019.
Singh repeatedly failed to declare the work and received $18,404 in compensation payments during that time.
WorkSafe Insurance Business Unit Executive Director Roger Arnold said the workers' compensation scheme was established to give injured workers the support and treatment they need to get well and return to work.
"The vast majority of injured workers are doing the right thing, but it's disappointing that a small minority think they can cheat the system," he said.
"Those who try to defraud the system for their own benefit will be held to account."
