Nearly $240,000 will be given back to Sydney hospitality workers after an investigation into 47 businesses found 77 per cent had breached workplace laws.
The Fair Work Ombudsman's surprise inspections uncovered one business had underpaid 18 casual workers and full-time employees $52,081.
Venues deemed "at risk" across Haymarket, Chinatown, Darling Harbour, Barangaroo, Surry Hills and Darlinghurst were targeted after a number of anonymous tip-offs.
They were also chosen if they had a history of non-compliance, or employed vulnerable migrant workers on international visas.
Many of the 333 workers found to have been exploited were young and vulnerable, Fair Work Ombudsman Sandra Parker said.
The investigation between May and June last year forms part of a national operation, including food precincts in Melbourne, Hobart, Perth, and Brisbane, that has so far recovered more than $2 million for workers.
Sydney's Glebe Point Road has also been targeted in the past.
Ms Parker said they were targeting "cheap eats" areas because figures for breaches were "not going down", and employers often took advantage of the system.
"What we have found across Australia when we've done audits of these food precincts … fast foods, restaurants and cafe sector … we have found very high levels of non-compliance," she said.
"Sydney is not really an outlier in that regard.
"It is a high-risk sector, it employs a lot of young people, they have high turnover of staff … low margins … they tend to employ a lot of visa holders, they are by their nature vulnerable workers."
Ms Parker said while business owners were surprised to see Fair Work officials at their door, they were often highly cooperative thereafter.
"If they are surprised and wanting to fix the issue, and they are willing to do that quickly and not get it wrong in future, we make sure they pay the money back and then we let the matter go," she said.
From the 36 businesses found to be in breach of workplace laws, 31 had underpaid workers, while 22 had failed to keep a record of payment.
The Fair Work Ombudsman also issued 27 infringement notices and $90,354 in fines. Another two businesses are still under investigation for alleged breaches.
