MPs have challenged Sports Direct over “deeply troubling” allegations from a whistle-blower that the retailer underpays its couriers.

The Work & Pensions and the Business, Energy and Industrial Strategy committees have received allegations from a Hermes courier that Sports Direct regularly underpays couriers by wrongly classifying packages.

Hermes pays two different rates for deliveries: one is for a packet weighing under a kilogram and the other for heavier parcels.

For customers, the rate for sending packets via courier is £3.29 while the rate for a couriered package is £10.49.

The whistle-blower alleges that Sports Direct regularly sends larger, heavier goods as packets and that couriers are paid much less as a result, saving both companies money.

They said that the Mike Ashley controlled organisation was “the most persistent company for this, [they] almost always send parcels through as packets”. They allege that recent examples included a bicycle.

The committees have written to Mike Ashley to try and obtain more information.

Work & Pensions Committee chair Frank Field MP said: “If this complaint stands up, it represents a new low in actually deliberately under-paying workers for the work they do.

“We look forward to a speedy response and if there is merit in these claims, an immediate change in working practices and proper compensation for workers who have been subjected to this.”

Business, Energy and Industrial Strategy Committee chair Rachel Reeves MP added: “On the face of it, this appears to be a stitch-up between Hermes and Sports Direct to short-change low paid couriers in order to boost company profits.

“It’s deeply concerning to hear reports that the paying of couriers at an artificially low rate could be a persistent practice in arrangements between these two companies.

“If we can’t rely on company boards and shareholders to stop these sorts of unethical practices, then tougher enforcement measures will need to be considered by the government and parliament.”

A Hermes spokesperson said: “We categorically deny these allegations and are happy to answer any questions raised. We have stringent processes in place to check that parcels are not mislabelled and placed in the wrong weight category.

“On the rare occasion of an individual label being incorrect, couriers can immediately call our dedicated courier support team, to notify us and change their payment with no questions asked. This applies to all our clients and ensures that both Hermes and our couriers receive the correct payment. We have no issues with Sports Direct who remain a valued customer.

“This year we have invested heavily in pay increases for our couriers, who now get paid a minimum of £8.50 per hour and an average of £11 per hour after expenses.”

Sports Direct did not respond to Retail Week’s request for comment.