The gas station drive-off debate this week has highlighted a wider issue, affecting people in low paid and low skilled jobs.

The practice of deducting the cost of stolen petrol from staff wages has come as no surprise to Canterbury University's Annick Masselot.

She says workers in precarious positions are often at risk of being exploited.

"It's quite easy to replace those workers and so therefore it's quite easy for employers to put very unsavoury and illegal conditions in their contract."

Associate professor Masselot says some workers don't know their rights, and are afraid they'll lose their jobs if they challenge an employer's decision.