A 7-Eleven wage theft case has exposed an unfair tax slug for some workers who win back pay, leading an appeals tribunal to call for changes to the law.

The administrative appeals tribunal has acknowledged a worker ripped off by 7-Eleven who fought and won a $62,000 lump sum in back pay ended up paying more in tax than he would have had he not been ripped off.

7-Eleven was the subject of a Herald and Age investigation into underpayment of employees. Credit:Glenn Hunt

But the tax office had applied the law correctly, the tribunal found, leaving the taxpayer out of pocket and the tribunal expressing sympathy over the “unfairness” and "unintended" consequences of the law.

It urged politicians to consider changing the law because “this unfairness is likely to be repeated” in an environment of "continuing ‘wage theft’".