Sacked Melbourne Grill'd employee Kahlani Pyrah has been reinstated by the burger chain after an interim ruling by the Federal Circuit Court, but she will not return to the workplace until a bullying claim is heard next month.

The ruling means she can proceed with a case to challenge Grill'd's 2007 workplace agreement, which is due to begin at the Fair Work Commission this week.

The judge also ruled Ms Pyrah would not actually work in the restaurant or be paid until a bullying claim is heard in late August.

Ms Pyrah, 20, was sacked in June after complaining about being underpaid.

She said she had been paid at a flat rate that was less than the award wage and did not receive shift loadings she was entitled to when she worked at the Camberwell restaurant.

"I just think it's really important that this happened because it shows that we don't have to be scared to stand up for our rights," Ms Pyrah said.

"I think that's been the most important part of the successful injunction to show all of my friends at Grill'd Camberwell and Grill'd stores across Australia and young workers in general that we can speak up."

The Victorian secretary of hospitality union United Voice, Jess Walsh, said there had been considerable community support for Ms Pyrah.

"Since Kahlani had the courage to speak out about this … dozens of other people have come forward and told similar stories of dodgy traineeships and underpayments at Grill'd," she said.

Last week the hamburger chain announced it would immediately review and renegotiate its workplace agreements after earlier saying many of the claims against it had been "factually incorrect".

In a statement, Grill'd managing director Simon Crowe said the company supported Ms Pyrah's stand at Fair Work Australia and agreed with the judge's decisions regarding the conditions of her reinstatement.

"We look forward to the [bullying] case being heard as promptly as possible ... so that the matter can be resolved once and for all," the statement said.