The Japanese operator of a ship that leaked oil off the Mauritius coast pledged Friday to pay at least $9.4 million to help restore areas affected by the spill.

Mitsui OSK Lines said in a statement that it planned "to contribute a total fund of about one billion Japanese yen over several years to support measures" to restore the marine environment.

The measures include running mangrove and coral protection projects in partnership with experts and local NGOs, and setting up an environment recovery fund, it said.

The company operates the MV Wakashio, which ran aground on July 25 off the coast of Mauritius, carrying 4,000 tonnes of fuel that began seeping into the island nation's pristine, coral-filled waters.

After the boat split in two, the larger piece was towed out to sea and sunk, but the smaller section remains stranded on the reef.

More than 1,000 tonnes of oil is believed to have leaked from the ship, with the rest siphoned out before it spilled.

The Japanese operator of a boat that spilled oil off the coast of Mauritius has pledged $9.4 million in funds to help clean-up and recovery efforts
The Japanese operator of a boat that spilled oil off the coast of Mauritius has pledged $9.4 million in funds to help clean-up and recovery efforts Satellite image ©2020 Maxar Technologies / Handout

The oil has affected mangroved areas that are complicated to clean.

Both the operator and the vessel's owner Nagashiki Shipping have apologised for the spill. Nagashiki last month pledged to "sincerely" respond to requests for compensation.

It was not immediately clear if the funds promised by Mitsui would satisfy demands from the Mauritius government for compensation from the companies for "all losses and damages" caused by the spill and clean-up costs.

Japan's Foreign Minister Toshimitsu Motegi said last week the country would continue supporting recovery efforts.

The accident is still under investigation by Mauritian authorities.

Japan's Kyodo News said last month the ship's crew had steered it close to shore because they wanted to find a mobile signal so they could contact family and ask about the coronavirus situation at home.

It cited an unnamed judicial source, who also said an alcohol-fuelled birthday party had been held on board before the accident, though it was not clear if on-duty crew participated.