Service station giant OTR has agreed to pay back — or credit — $2.3 million in annual leave entitlements to 1,500 current and former employees in South Australia, Victoria and Western Australia after a Fair Work Ombudsman (FWO) investigation.

The FWO inspected 15 OTR sites and found that employees had not been classified as shift workers when they should have been.

Shift workers are entitled to five weeks of annual leave, not the standard four for non-shift workers.

Ombudsman Anna Booth said questions raised by employees at OTR — short for “On The Run” — led to the investigation.

“We got a lot of inquiries to our info line about the categorising of employment, [with] workers believing they were shift workers and they should be receiving annual leave as such,” Ms Booth said.

“We investigated and found that they were correct … and we brought this to the attention of the employer.”

Ombudsman Anna Booth described the loss of leave as “troubling”.(Supplied: Fair Work Ombudsman)

Ms Booth said that OTR then conducted its own review, which found a total of 1,524 OTR workers had not received their annual leave entitlement between July 2018 and February 2023.

“It is troubling, it does make you wonder about how much attention was being paid,” Ms Booth said.

OTR has since signed an enforceable undertaking and has agreed to repay 934 former employees a total of $975,000, which includes $48,415 in interest.

About 6,000 days of annual leave, worth about $1.3 million, have also been credited to 590 employees who still work at OTR.

The ABC has contacted OTR for comment.

‘Serve as a warning’

The company has more than 150 stores across Australia, is one of the biggest employers in SA, and also has a presence in Victoria and WA.

Most of the affected workers were from SA and worked at service stations and other OTR businesses in areas including Adelaide, Bordertown, Ceduna, Port Lincoln, Port Augusta and Murray Bridge.

A smaller number of employees worked in Perth, and in Victoria at Horsham, Mildura, Ararat and Traralgon.

The ombudsman said the largest single back payment to an employee was $6,189, while one current employee was given back 24 days of annual leave.

“The positive out of it, and why we’ve entered into an enforceable undertaking with On The Run, is that they have fully cooperated with us,” Ms Booth said.

“They have undertaken remediation and they have committed to undertaking processes that ensure that it doesn’t happen again.”

OTR is one of the biggest employers in South Australia.(ABC News: Che Chorley)

Ms Booth said OTR has also agreed to pay a $150,000 “contrition payment” to the federal government’s consolidated revenue fund.

“That’s really just a payment that says … we’re sorry and we acknowledge and take responsibility for our mistake,” she said.

Ms Booth said the situation should “serve as a warning to all employers”.

“In this case, it was a failure to categorise its workers as shift workers but it can be other mis-categorisations too,” she said.

“This is not a complex issue — it’s about the hours of work and the pattern of work, and knowing that your worker is a shift worker is something I would expect an employer to know.”

Ms Booth said she also expected the new OTR owners, Viva Energy, to follow through on the agreement reached with OTR and assure the “community and employees that this will not happen again”.