The wreck of a chemical ship that caught fire off the Sri Lankan coast and caused environmental carnage will be removed, the operators said Wednesday.

A salvage company has been contracted to remove the sunken MV X-Press Pearl and the remains of its cargo, its Singapore-based managers said.

"The wreck removal plan will ensure a complete removal and safe, proper disposal of the wreck and any debris and pollutants around the wreck," X-Press Feeders said in a statement.

Hundreds of tonnes of chemicals and plastics leaked from the ship after it caught fire in May off Colombo and burned for two weeks before sinking.

Dead turtles, dolphins and whales washed up on the Indian Ocean island's beaches, and Sri Lankan authorities said it was the country's worst marine disaster.

The vessel was known to be carrying 81 containers of hazardous chemicals, including 25 tonnes of nitric acid, when it caught fire.

Around 1,200 tonnes of tiny plastic pellets and other debris that blanketed beaches have been scooped up and stored in 45 shipping containers.

Sri Lanka sought $40 million in damages from the ship's operators to cover the initial operational costs incurred in handling the disaster.

RTL

The sinking of the MV X-Press Pearl was the worst marine disaster in Sri Lanka's history, authorities said / © AFP/File

A second compensation claim has been submitted by Sri Lankan authorities, the operators said.

But the wider ecological costs are yet to be determined, according to the island's Marine Protection Authority.

Its chair Darshani Lahandapura welcomed the salvage plan.

"We have to start it soon as the rough sea season is fast approaching," she said. "This is going to take time, not an easy thing to do."

University professor and environmentalist Terney Pradeep Kumara added that removing the wreck was "absolutely necessary".

But he said it would lead to a spike in pollution "due to the clearing of the containers carrying chemicals which are deposited in the sea bed alongside the wreck".

Sri Lanka in June launched a criminal probe against the ship's captain, chief engineer, chief officer as well as its local agent.