France launched a hunt for more wreckage from the ill-fated MH370 plane off Reunion island on Friday in a fresh effort to shed light on one of aviation's biggest mysteries.

The tiny French Indian Ocean territory has been under intense scrutiny since a beach cleaner found a washed-up wing part last week, which Malaysian Prime Minister Najib Razak later declared was part of the Boeing 777 that mysteriously vanished 17 months ago.

READ:PM Najib Razak's full statement on MH370

The flaperon is currently being examined by experts in southern France for possible clues as to why the Malaysia Airlines aircraft inexplicably veered off course en route from Kuala Lumpur to Beijing, and there are hopes that Reunion may yield more washed-up debris.

In nearby Mauritius, authorities are also searching for any possible plane parts that may have landed on their shores.

Aline Simon, a French officer, told AFP a military transport plane had taken off from a base in the north of Reunion island to search for debris off the coast.

False alarms

The hunt for potential plane parts will also involve foot patrols, helicopters and maritime units, the government said in a statement late Thursday.

Since the discovery of the two-metre-long flaperon last week, people on the island have come forward with countless objects they think may look like plane parts -- all false alarms.

Malaysian Transport Minister Liow Tiong Lai said Thursday that more possible MH370 objects -- aircraft seat cushions and windows -- had been discovered on Reunion island, but that any MH370 link "had to be verified by the French authorities."

A French judicial source however said French investigators had not received any new items.

The Boeing 777 disappeared on March 8 last year, sparking the largest search operation in history, now focused on the southern Indian Ocean based on satellite data hinting at the plane's path.

Australian authorities, which are leading the search, expressed renewed confidence that they were looking in the right area.

"The finding of this piece of wing gives us hope that we are searching in the right location, given the tides and currents and drift patterns," Foreign Minister Julie Bishop told Australian television from Malaysia.

French prosecutors involved in the analysis of the flaperon have however been more cautious, saying only that there was a "very high probability" it came from the Boeing 777.

But Liow said on Thursday that certain characteristics of the wing part, including its paint, matched MH370 maintenance records -- backing up Najib's announcement that it was part of the plane.

'No conclusive evidence'

Najib's televised statement was not universally welcomed by relatives of the 239 people on board the jet, with some expressing scepticism and fresh criticism of officials' handling of the disaster.

"There is no conclusive evidence that this part belongs to the Boeing," said Ghislain Wattrelos, who lost his wife and two of his children on the flight.

"It's not 100 percent (sure) like the Malaysian prime minister said."

Some anguished family members nevertheless said the first concrete proof of the plane's fate would help bring closure.

"We've had 17 months of nothing... so actually finding something is the first step towards pinpointing where it is," Sara Weeks, the sister of MH370 passenger Paul Weeks, told the Fairfax New Zealand media group.

Chinese relatives of passengers aboard MH370 marched to Malaysia's embassy in Beijing on Friday, some demanding to be taken to Reunion.

"We want to go to the island and see the truth," said Lu Zhanzhong, whose son was on the plane.

Analysts call the flaperon find a clear step forward by eliminating theories that the plane might have landed somewhere, and confirming the search was roughly on the right track.

But they caution that only by locating a crash site and recovering the black box are authorities likely to help solve the mystery, unless new evidence emerges elsewhere.

It is hoped that more detailed examination of the wing part in the coming days may indicate how it detached from the aircraft and whether it showed traces of an explosion or fire.