Bad weather is delaying an operation to remove the wreck of a Japanese fuel tanker that ran aground on a coral reef off Mauritius, local media and an environmental expert say.

The tanker, which was carrying 4000 tonnes of fuel oil when it ran aground near the Indian Ocean island on July 25, has leaked about 1000 tonnes of its cargo into the popular honeymoon resort’s pristine coastal waters.

The front part of the vessel, which on Saturday afternoon split in two on the reefs of Pointe d’Esny, had drifted about 30 metres, director of maritime affairs Alain Donat told newspaper Le Mauricien.

The front part was supposed to be towed away on Saturday and sunk at least 1000 kilometres away from Mauritius, but bad weather delayed the operation.

The Japanese owned, Panama-flagged bulk carrier after it ran aground off the south-east coast of Mauritius. Photo: EPA

The rear section of the ship will initially be left on the breakers, Mr Donat was quoted as saying.

“The part has drifted, so there is a lot of effort to try to get it to the high sea,” independent environmental consultant Sunil Korwarkasing told DPA.

What to do with the rear section was still under discussion with local authorities, Nagashiki Shipping, the Japanese owner of the tanker, said on Sunday.

Forty tonnes of fuel oil remained inside the MV Wakashio on Sunday, which authorities were trying to remove before it spilled into the ocean, said Mr Korwarkasing, quoting the national police commissioner.

Japanese Environment Minister Shinjiro Koizumi told reporters on Saturday he was planning to dispatch a team of ministry officials and experts to Mauritius to grasp the extent of the damage.

On Thursday, Nagashiki Shipping said it had removed almost all of the remaining 3000 tonnes of fuel oil.

Mauritius declared an environmental state of emergency last week, but authorities have been accused of being slow to act.

-AAP