Malaysia, China and Australia will meet in September to "refine" the search for Malaysia Airlines flight MH370 after part of the plane's wing was discovered on an Indian Ocean island last month, more than a year on from the aircraft's tragic disappearance.

Malaysia's Prime Minister Najib Razak said on August 5 that experts had "conclusively confirmed" that the debris found on the French island of Reunion - a piece of the wing known as the "flaperon" - came from the doomed flight, which vanished 17 months ago in one of aviation's greatest mysteries.

However, French investigators were more cautious, saying only there was a "very high probability" that the flaperon came from the plane, sparking anger from relatives over the ambiguity.

"With the discovery of the flaperon, we have to sit down with Australia and China to map the way forward to find the plane," Malaysia's Deputy Transport Minister Abdul Aziz Kaprawi told AFP.

"We hope to refine and prioritise the search efforts. Definitely, the search will continue in the same area," he said, adding that officials were working out the date for the gathering and the host for the meeting.

The jet disappeared from radar on March 8 last year after mysteriously veering off its original flight path from Kuala Lumpur to Beijing.

Investigators believe the aircraft ran out of fuel and crashed somewhere in the southern Indian Ocean.

Of the 239 people on board, the majority were Malaysians and Chinese.

Australia has been leading the search for the plane, the largest multinational search operation in history.

More than 60,000 square kilometres of the sea floor have been searched, with no trace of the missing Boeing 777 found until last month's discovery.

It was announced in April that the search area could be expanded up to 120,000 square kilometres if needed.