Brisbane burger chain Miel Container Pty Ltd allegedly underpaid 11 overseas workers for three years. The Fair Work Ombudsman has started legal action against the gourmet burger outlet for more than $155,000 in underpayments of its South Korean workers from 2013 to 2016.

The workplace watchdog said Miel Container underpaid eight employees at the CBD outlet $111,652.09 between 2013 and 2016, while HWMJ Pty Ltd, which also operates the burger chain outlets, underpaid five employees at the Sunnybank outlet $44,162.20 for seven months in 2016.

The casually employed workers, all South Korean nationals who had working holiday and student visas, were generally paid a flat rate from $10 to 16 per hour. Under the Restaurant Industry Award 2010 at the time, they were supposed to be paid $20.61 per hour for ordinary hours and higher amount for weekend, public holiday and overtime work. Most of the workers spoke limited English and the youngest was just 19. The alleged underpayments of each worker range from $3,212 to $25,432.

Facing court are Sangmoon “Johnny” Na, the sole director of both Miel Container and HWMJ, and his brother Sanghoon Na, an owner and manager of the Sunnybank outlet. According to the Fair Work Ombudsman, Sangmoon is involved in some underpayments, as well as record-keeping and pay slip contraventions at both CBD and Sunnybank outlets. Sanghoon, meanwhile, is allegedly involved in some record-keeping contraventions at the Sunnybank outlet.

“We treat exploitation of overseas workers particularly seriously because we know they can be vulnerable if they are not fully aware of their rights, face language barriers or are reluctant to complaint,” Acting Fair Work Ombudsman Kristen Hannah said in a statement. “We are committed to actively pursuing and holding to account any employer in Australia who thinks they can get away exploiting overseas workers.”

Miel Container and HWMJ face penalties of $54,000 per contravention, while the Na brothers each face penalties of up to $10,800 per contravention. The Fair Work Ombudsman will seek for full back payment of the employees.

The agency recently published an open letter to international students, encouraging them to seek help if they have employment issues in Australia. It has forged an agreement with the Department of Immigration and Border Protection so students can seek assistance without fear of their visa getting cancelled, even if they have worked more hours than their visa allows.