Package delivery firms have been told to improve working conditions at their depots after labour inspectors found they were in breach of health and safety rules.

All six of the largest delivery companies in the Netherlands – PostNL, DHL, DPD, FedEx, GLS and UPS – were served warning notices after labour inspectors said the intense workload was putting workers’ health at risk.

“Workers in package delivery companies’ depots – mostly agency workers and often labour migrants – work under excessively hard physical conditions,” the labour inspectorate said in a report.

“Unsuitable working practices can cause physical strain and damage to health.”

Workers were required to load and unload pallets and lift heavy packages by hand because of the lack of automation in storage depots, the inspectors said. “Loads are too heavy, both below the knee and above the shoulders,” they said.

The inspectors also expressed concern about the high working tempo as companies strive to meet demand in a sector where next-day delivery has become the norm.

The report calls on companies to implement a range of improvements to protect workers’ physical health, including more mechanical assistance, limiting the maximum load of carts, rotating tasks on the factory floor and training in safe working practices.

A second round of inspections will be carried out next year at the 35 depots and enforcement measures taken if necessary, the inspectorate added.