The Fair Work Ombudsman says she is concerned petrol station giant United Petroleum has described staff underpayment as “minor”.

The Ombudsman investigated 11 randomly selected franchises around the country, and found six were breaking workplace laws and underpaying staff thousands of dollars.

“We clearly found issues of non-compliance at more than half of those outlets. That’s a disturbing finding,” Fair Work Ombudsman spokesman Craig Bildstien told the ABC.

In a statement to the ABC, United Petroleum repeatedly described the underpayments as “minor”.

“These minor underpayments were due to the incorrect interpretation of penalty rates and in some cases human error. These instances of minor underpayments have been rectified (except for one person who cannot yet be found),” the statement said.

The Ombudsman found one United site in Adelaide underpaid five Indian students a total of $2,032 over five months.

The operators of a Sydney site underpaid three international students from India and Bangladesh a total of $3,096.

Staff at both sites were paid about $18 an hour, compared to the award rate of $25.05 Monday to Friday, and $32.56 on the weekend.

Both operators have co-operated with the Fair Work Ombudsman and agreed to reimburse staff.

Fair Work Ombudsman Natalie James tweeted on social media: “Concerned underpayments are described by @UnitedPetroleum as ‘minor’. Not to these min wage workers!”

The Fair Work Ombudsman finds six United Petroleum service stations across Australia breaking workplace laws, including underpaying staff thousands of dollars.

The regulator launched its investigation last year after the ABC reported staff at some United Petroleum sites were being underpaid, with two former managers alleging they had told head office but were ignored.

United Petroleum head office denied the allegations.

The Fair Work Ombudsman said it wrote to United Petroleum head office about its investigation in December 2015, but United Petroleum did not respond.

“We invited them to participate in a compliance partnership with us but unfortunately they didn’t respond. So when we met their senior officials two weeks ago to bring them up to speed on our investigation, we put that offer back on the table, we reissued the invitation and we are yet to hear back,” Mr Bildstien said.

After news of the underpayment broke, United Petroleum’s lawyers wrote to the FairWork Ombudsman advising that the company was prepared to meet later this year to discus the issue.

Extracted in full from ABC.