The local arm of Japanese burger chain, MOS Burger, has been caught underpaying its Australian workers $1.1 million over a period of seven years.

Key points: MOS Burger is the second largest burger chain in Japan, after McDonald's

MOS Burger is the second largest burger chain in Japan, after McDonald's It underpaid 285 staff in Queensland between 2011 and 2018

It underpaid 285 staff in Queensland between 2011 and 2018 The company repaid workers more than $1m after being investigated by the FWO

MOS Burger Australia paid "unlawfully low rates" and "misclassified" some of its casual workers (who are meant to be paid higher rates) as part-time employees, according to the Fair Work Ombudsman (FWO).

The workplace regulator found that many of the 285 underpaid staff were either visa holders or young workers.

Outstanding wages ranged from $18 to $31,975 — which takes the average underpayment to about $3,900 per worker between 2011 and 2018.

MOS Burger has a relatively low profile in Australia with six stores in Queensland — located in Brisbane, Surfers Paradise, Southport, Broadbeach, Sunnybank and Mt Gravatt.

But it is a major franchise across Asia, with more than 1,700 stores across Japan, Taiwan, Singapore, Hong Kong, Thailand, Indonesia, China and South Korea.

It is also one of the largest burgers chain in Japan, second only to McDonald's.

After being investigated by the regulator, MOS Burger signed a court-enforceable undertaking.

Essentially, the burger chain agreed not to breach workplace laws again, otherwise it will be prosecuted by the Ombudsman.

The company has also repaid its staff their missing wages and superannuation, and paid them an additional 7 per cent compensation, the FWO noted.

MOS Burger has six stores in Queensland, but more than 1,700 restaurants across Asia. (Supplied: Westfield)

In this situation, it was an "appropriate enforcement tool", Fair Work Ombudsman Sandra Parker said.

Ms Parker said it was because MOS Burger "conducted a comprehensive audit of its pay records from when it commenced trading in Australia, fully back-paid workers and overhauled its processes to comply with workplace laws".

The company also agreed to fund external auditors to check that it is paying staff correctly in 2019 and 2020.

MOS Burger joins a long list of businesses which have been in the spotlight for underpaying their staff.

In the hospital industry, high-end restaurant Rockpool and celebrity chef George Calombaris's restaurant empire have also recently had wage scandals.

Cosmetics retailer Lush, Super Retail Group (known for its Rebel Sport stores), Qantas, Bunnings, Commonwealth Bank, jewellery chain Michael Hill, Woolworths and the ABC have also underpaid their staff.