These robots are sorting out packages faster than you can say delivery.

A video showing an army of tiny little yellow robots sorting out packages in a Chinese factory is the latest example of how automation is seeping into many industries.

The Shentong Express (STO) factory in Tianjin is China's largest fully automated sorting plant in the delivery industry.

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The robots can be seen carrying their parcels away to different areas across the sorting centre, then depositing them into underground chutes.

Once in the plant, all packages get distributed within just three-and-a-half hours.

In the past, it took at least 100 experienced workers to do the same job in the same time.

The robots work across a 2,000 square metre area (21,000 sq ft) and between them, they generate at least 300 billion route combinations -- which requires a huge amount of calculations at its backend.

"The total amount of calculations completed by our automated system in five minutes is equivalent to the daily takeoff and landing calculations done at Beijing Capital International Airport, said Ge Zhi Zhong, manager of STO express' logistic department in Tianjin in the video.

And this isn't STO's first robot army either.

The company also has a warehouse in the Chinese city of Hangzhou, where little orange robots do exactly the same job.

According to the South China Morning Post, the machines can sort up to 200,000 packages a day and are self-charging -- so they can continue going 24/7.

An STO spokesman also added that the robots had helped the company save half the costs it typically required to use human workers.

In 2016 alone, 30 billion packages were delivered across China.