Nagashiki Shipping has reportedly apologised for the grounding of one of its bulkers on a coral reef offshore Mauritius, that has caused a highly polluting spill of bunker fuel.

"We sincerely apologise for causing a great deal of inconvenience to everyone involved, including everyone in Mauritius, due to this grounding accident and oil spill," the Japanese company said in a statement obtained by Reuters.

Low-profile, 150-year-old Nagashiki managed the capesize bulker before it ran around on 25 July, spilled 1,000 tonnes of fuel oil and broke in two over the weekend.

It also shares an address with the ship's registered owner Okiyo Maritime.

The spill is considered Mauritius' worst ever environmental disaster, with the spill threatening the reef, fish and other marine life.

Reuters also reported the country plans to scuttle the ship at a later date somewhere at sea that would not impact shipping lanes or pollute the Indian Ocean any further.

The news follows reports on Tuesday that authorities in the country had arrested the ship's captain, 58-year-old Indian national Sunil Kumar Nandeshwar and another unnamed officer for endangering safe navigation and that the ship's bow section was under tow.

The Wakashio was under charter to Mitsui OSK Lines when the grounding occurred. The company said the ship was 20 miles off course when it ran into the reef.

Unconfirmed reports suggest the ship was in search of a wireless internet connection during a birthday party for one of the crew members.

Japan has reportedly sent a team of oil spill experts to the country to assist in remediation.