The "blind box" craze sees people order a box containing an animal that is then sent to them through the post.

On Monday, 160 distressed cats and dogs were located inside a courier company's truck in Chengdu.

It has prompted calls for action on the phenomenon as well as on the purchase of animals online in general.

According to Chinese law the transportation of live animals is prohibited, but "blind boxes" are incredibly popular, state media reports.

A range of the boxes containing animals such as tortoises, lizards and rats have been reported for sale on sites such as Taobao.

On Monday animal rescue group Chengdu Aizhijia Animal Rescue Centre said it had intercepted a vehicle carrying 160 dogs and cats, all under three months old. It said a number of them had died.

The group posted video footage of the boxes piled up to the ceiling of the truck on social media site Weibo.

"The cargo box is full of screams from cats and puppies," the group wrote.

Volunteers stayed with the animals throughout the night, feeding them and giving them water, while they underwent health inspections.

The rescue centre announced on Thursday that it had managed to bring the animals back to their base for resettlement and a further 38 were receiving medical treatment.

The courier company involved, ZTO, said the person in charge of delivery safety in Sichuan province has been suspended and his annual performance bonus had been deducted.

It confirmed that it had broken China's postal regulations and apologised to members of the public, People's Daily Online reported.

ZTO also said it had launched additional training regarding postal safety and national animal protection.

The incident has caused outrage on social media with people calling for a boycott of such boxes and buying animals online. The phrase "pet blind box" has had millions of views on Weibo.

"Have we made any achievements in the rescue and management of stray animals? Now there is a pet blind box industry?" one user wrote.

Another wrote: "Let's talk about boycotting pet blind boxes again. What they need is a home, not an uncertain possibility".

State media Xinhua described pet "Blind boxes" as a "Desecration of life" and said courier companies and e-commerce platforms must "strengthen self-examination and self-correction".

It also called on buyers and sellers to have "More goodwill and more respect for life".