More than 120 former employees at the Newcastle Airport are to be back paid more than $472,000 after it was found they were being short changed, with one employee reportedly underpaid more than $28,000.

They worked at Hungry Jack’s and the Sports Bar and Bistro before both businesses closed in March this year.

Wage errors were uncovered after one of the workers approached the Fair Work Ombudsman for assistance.

The former owner operator of the two businesses, Marriott Airport Concessions, was mistakenly paying its casual staff a flat hourly rate.

Staff should have been paid according to the terms of the Restaurant Industry Award, and the Fast Food Industry Award.

The employee who first complained was short changed $15,596 over three years to November, 2013.

Follow up calculations revealed that 123 employees engaged between July 1, 2010 and January 10, 2014 had been underpaid a total of $472,258.

Marriott has so far back paid $74,671 and has committed to reimbursing all outstanding entitlements over two years.

The company has also entered into an Enforceable Undertaking (EU) with the Fair Work Ombudsman to revamp its workplace practices. This includes an independent audit of the wages of at least 30 per cent of its casual employees once a year for the next three years.

Fair Work Ombudsman, Natalie James, said the issue highlights how a mistake left over time can result in a hefty bill for back payment of wages.

“This matter demonstrates how lack of awareness or ignorance of minimum wages and conditions can potentially have a negative financial impact on the business.

“It should also show how our intervention can assist employers to become compliant and minimise potential negative effects on business if workplace laws are not observed,” James said.