A Melbourne company which underpaid young and overseas workers at two Burger Buzz outlets has been fined over $300,000 by the Federal Circuit Court.

Rum Runner Trading and business owner Todd Patrick Buzza were taken to court by the Fair Work Ombudsman twice after Mr Buzza failed to back-pay former staff.

The Fair Work Ombudsman first took Mr Buzza to court in 2016 on behalf of four backpackers and three Australian staff who were owed between $452 and $1,522 for work at Burger Buzz outlets in Brunswick and West Melbourne which are now closed.

In 2017, they took Mr Buzza to court again alleging he owed another five workers a total of $7,513.

Mr Buzza was not in court when the penalty was handed down. He was personally fined $54,735 and his company was fined $258,495.

Jess Gordon was offered a job at Burger Buzz in Brunswick shortly after she moved to Melbourne for university at the start of 2017.

"I had practically no money, was living with a friend and need a job ASAP," she said.

On her third shift, Ms Gordon said a French girl came in asking to see Mr Buzza.

"She informs me that Todd never paid her for three weeks of work dating back some months ago," she said.

Ms Gordon asked Mr Buzza to pay her for the 25 hours work she had done but she said he never paid her the money.

"So typical. I was 21, new, no family here, desperate," she said.

Ombudsman Natalie James said Mr Buzza had used a business model that involved "churning through and exploiting vulnerable workers for his own benefit".

Five of the employees were paid nothing and most of the others were paid less than half what they were entitled to.

Mr Buzza and his company were ordered to give the workers back-pay in June last year but he has not done so.

Burger Buzz is now closed and Mr Buzza was not in court for the hearing. ( ABC News: Danielle Bonica )

'Serves him right'

Wesley Barros did a trial shift at Burger Buzz in Brunswick in 2016.

"I was unemployed at the time and did a resume run up Sydney Rd. I spoke directly to Todd, he sat me down and said I'll get you in for a trial shift next week," he said.

Mr Barros said Mr Buzza promised to pay him $20 an hour for the eight-hour trial shift, after which Mr Barros would get 30 hours work a week.

"I said I'd take the job and gave him my bank details," Mr Barros said.

"I never received payment for the trial shift. I messaged him about once a week for three months, never heard anything back from him," he said.

Mr Barros is glad the Fair Work Ombudsman has taken Mr Buzza to court.

"It serves him right," he said.

This is not the first time Mr Buzza has been singled out for dodgy business practices.

Consumer Affairs Victoria has warned the public against doing business with the former bankrupt businessman.

In a public warning issued in 2013 it said "Consumer Affairs Victoria has received complaints alleging Mr Buzza has taken payment for work he has not done, or for work that was incomplete and below standard" when he was trading under a number of building businesses.

The ABC has been unable to reach Mr Buzza for comment.