George Calombaris' hospitality empire says it will reimburse underpaid staff within a month, following criticism of the compensation scheme which included social media attacks on the celebrity chef.

Fairfax Media revealed last week that Mr Calombaris' company, Made Establishment, had told former staff they could be forced to wait until June 2018 before receiving back-pay for missing wages and entitlements.

Last month Made Establishment chief executive Troy McDonagh told former employees that the deadline would be extended by 12 months because "the total number of individual investigations we have taken to properly and accurately assess each claim is substantially greater than what we first anticipated".

The delay had frustrated the Fair Work Ombudsman, and sparked a campaign of abuse against Mr Calombaris, which included signs posted around Melbourne's CBD with a photograph of the Masterchef star under a headline which read: "Does this guy owe you money?".