The British government has launched an investigation after Sri Lankan authorities said they would send back more than hundred shipping containers because they appeared to contain human remains disguised as recyclable metals.

Officials at the port of Colombo made the grisly discovery while investigating a strong smell emanating from 111 containers which have been arriving at the docks over the past two years.

Inside the crates, customs officials found the “extremely hazardous” materials mixed in with mattresses, plastics and clinical waste.

Defra was on Tuesday night investigating reports that human organs and body parts were inside the container, but said it was yet to be approached by the Sri Lankan authorities.

"We are committed to tackling illegal waste exports, which is why individuals found to be exporting incorrectly described waste can face a two year jail term or an unlimited fine," a spokeswoman said.

“We are yet to receive a formal request from the Sri Lankan authorities, but Defra has contacted them directly to find out more information.”

"This is a well-organised racket that has been going on since 2017," said an official at Sri Lanka’s finance ministry, adding that they would raise the issue with the British authorities.