The Fair Work Ombudsman launched a series of raids in Wollongong in response to concerns young workers in the town were being exploited.

Fair Work inspectors visited more than 80 businesses unannounced in the city's central business district across three days this week.

The raids are in the wake of Fairfax Media's exposure of widespread underpayment and in cases non-payment of university students by cafes, restaurants, retail and take-away food outlets.

Inspectors interviewed business operators and workers and checked records to ensure workers were being paid minimum hourly pay rates, penalty rates, overtime and allowances. Their compliance with record-keeping and pay slip laws was also checked.

Acting Fair Work Ombudsman Michael Campbell said the auditing was in response to intelligence and public concerns that young workers in Wollongong were being underpaid and treated unfairly. He said a number of audits could lead to full blown investigations.

Inspectors contacted young workers identified by Fairfax Media before targeting the businesses that employ many young workers.

"Wollongong is a tertiary education hub with a high a number of young students who work in casual jobs and the reports of underpayments have been concerning," Mr Campbell said.

"Young workers can be vulnerable if they are not fully aware of their rights or reluctant to complain, so it's important we are proactive about checking they're being paid correctly."

After taking to Facebook to vent about being offered as little as $10 per hour to work in a takeaway food shop in Wollongong last year, Wollongong University graduate Ashleigh Mounser received complaints from about 67 young workers with similar issues.

Fairfax Media has spent two months talking with many of these workers, including Ms Mounser and her original Facebook respondents, their employers and researchers about the underpayment of workers aged 18 to 24.

Not only were young people in the Illawarra being ripped off, in an area of high youth unemployment, many were working for free in the hope of getting a paid job.

Ms Mounser welcomed news of the raids on businesses, but said more needed to be done to stop the rampant underpayment of students from continuing.

"I'm glad that something is being done, but I would rather that it be prevented rather than punished," she said.

"I think we still need to look at legislation in terms of preventing it because people are still coming to Wollongong and dealing with the same problem, even it it's from a different business."

Arthur Rorris, secretary of the South Coast Labour Council, the peak union body for the region, said Ms Mounser had uncovered a culture of exploitation.

"We are not surprised that the Ombudsman has conducted these raids. It will take much more than three days of raids to get to the heart of the problem," he said.

"We are talking about hundreds of businesses in our region and thousands around the country."

Mr Rorris said the labour council has so far recovered thousands of dollars of entitlements for workers who have spoken up about the underpayment problem.

"We are in the process of recovering more in the coming weeks and months," he said.