Amazon is at the centre of a fresh storm over the use of zero-hour contracts for temporary workers.

Workers who took jobs working in the etail titan’s warehouses in the run-up to Christmas have claimed they were put on controversial zero-hour deals – a move that goes against Amazon’s policy to never use such contracts and its pledge to pay everyone for a guaranteed 20 hours a week.

An investigation by ITV News, the Bureau of Investigative Journalism and the Daily Mirror analysed 9,000 adverts posted for Amazon roles on the UK’s biggest recruiting website ahead of the crucial golden quarter last year. Each of the ads was posted by Adecco or PMP Recruitment – recruitment agencies hired by Amazon.

But workers taking up the positions said they felt “exploited and expendable” because shifts were often cancelled at the last minute.

In some weeks, they were left without any shifts at all, despite being offered part-time or full-time hours when taking on the positions.

One temporary worker also said her wages were calculated incorrectly and she was only able to reclaim the £400 owed to her by Adecco two months after leaving the role.

An Amazon spokesman said: “We created 20,000 seasonal positions for the festive period across the country. Our agency terms are explicit that we do not engage individuals on zero-hour contracts.

“Associates on temporary assignments at Amazon, who are employed by agencies, work a range of shifts from full-time to part-time; however, in the majority of cases, a 40-hour week is offered.”

Adecco said: “The welfare of our associates is an absolute priority for us and we work closely with clients to ensure they have the best possible experience.

“Associates are paid fairly and we offer up to 40-hours per week of work, part-time or flexible shifts.

“We are in regular communication with all our associates to ensure they have a clear understanding of their work assignments.”

PMP Recruitment added: “Temporary recruitment agencies such as PMP exist to support the flexible labour requirements of customers.

“As a result, we are unable to offer our workforce full-time guaranteed hour contracts but we do, on a regular basis, offer 40-hour weeks or hours to suit personal circumstances.

“In this specific case, our colleagues are not employed under zero-hour contracts and are provided with a guaranteed minimum number of shifts per week.”