Nearly 200 staff at George Calombaris' restaurants have been underpaid NZ$2.8 million, with the chef blaming "historically poor processes" for the mistake.
Celebrity chef Calombaris is known for being a judge on the hit reality television show MasterChef Australia since 2009. He also owns a series of Melbourne restaurants under the Made Establishment Group, including signature restaurants The Press Club, Gazi and Hellenic Republic.
Calombaris underpaid 162 of the 430 current staff at restaurants including those that form part of the group over the past six years.
Staff were not paid the correct salaries or overtime due to the "poor processes in classifying employees", Calombaris told Fairfax.
In an email to staff, Calombaris said: "You, our amazing team, are the key to our success and I am so sorry we have messed up and let you down on a fundamental, which is to ensure our people are paid what they are entitled to.
I am devastated ... we have been working extremely hard to fix this.
"I want to be clear that getting it right means ensuring that every single team member is paid what they are entitled to under the existing award and that any outstanding money owed to staff is rectified as our highest priority."
He is currently in Japan filming a new season of Masterchef Australia, but says he will be back by the end of the week when he will address his staff.
CEO of the Made group Troy McDonagh said the celebrity chef has "reached out to all the team".
"He's absolutely in this every step of the way and he's really excited to come back after filming in Japan on Friday and his first plan on Friday is to get out and meet the team and make sure everything is as it should be," he said.
Staff at Jimmy Grants, a souvlaki bar launched in 2013, were not affected by the underpayment issue, according to management.