Bill Shorten has written to Prime Minister Malcolm Turnbull urging him to grant an amnesty to thousands of exploited 7-Eleven workers.

The Opposition Leader wrote to Mr Turnbull on Friday, pleading for a reprieve for up to 4000 international students, some of whom were paid as little as $5 per hour.

"Although 7-Eleven has established a company funded investigation headed by Professor Allan Fels AO and a Senate inquiry is examining this matter, I believe the gravity of the breaches involved in this case warrants the public release of any Fair Work Ombudsman inquiry," Mr Shorten said.

"I also ask that the government consider providing a visa amnesty to affected workers to help them pursue their workplace rights, given the unique circumstances and unprecedented scale of this particular case. I understand that many underpaid employees may be reluctant to come forward with their underpayment claims unless an amnesty is granted in respect of their student visas," he wrote.

Mr Shorten's request for an amnesty is the same as that made by class action law firm Maurice Blackburn. Principal Josh Bornstein has also written to Mr Turnbull saying the investigation, which relies on current and former staff who have been exploited giving evidence, will not work properly unless a reprieve is granted. The Department of Immigration has previously said it is considering an amnesty. A spokesman for the Minister Peter Dutton could not be reached.