A viral video showing an army of little orange robots sorting out packages in a warehouse in eastern China is the latest example of how machines are increasingly taking over menial factory work on the mainland.

The behind-the-scenes footage of the self-charging robot army in a sorting centre of Chinese delivery powerhouse Shentong (STO) Express was shared on People’s Daily’s social media accounts on Sunday.

The video showed dozens of round orange Hikvision robots – each the size of a seat cushion – swivelling across the floor of the large warehouse in Hangzhou, Zhejiang province.

A worker was seen feeding each robot with a package before the machines carried the parcels away to different areas around the sorting centre, then flipping their lids to deposit them into chutes beneath the floor.

The robots identified the destination of each package by scanning a code on the parcel, thus minimising sorting mistakes, according to the video.

The machines can sort up to 200,000 packages a day and are self-charging, meaning they can operate around the clock.

An STO Express spokesman told the South China Morning Post on Monday that the robots had helped the company save half the costs it typically required to use human workers.

They also improved efficiency by around 30 per cent and maximised sorting accuracy, he said.

“We use these robots in two of our centres in Hangzhou right now,” the spokesman said. “We want to start using these across the country, especially in our bigger centres.”

Although the machines could run around the clock, they were presently used only for about six or seven hours each time from 6pm, he said.

Manufacturers across China have been increasingly replacing human workers with machines.

The output of industrial robots in the country grew 30.4 per cent last year.

In the country’s latest five-year plan, the central government set a target aiming for annual production of these robots to reach 100,000 by 2020.

Apple’s supplier Foxconn last year replaced 60,000 factory workers with robots.