Two objects, including one measuring up to 79ft long which some experts say is almost the same length of a wing from the missing Boeing 777's and another 16ft in length were photographed five days ago.
Malaysia's government described it as a 'credible lead'.
The country's leaders have faced intense criticism over the search efforts since the Kuala Lumpur to Beijing flight vanished with 239 people on board early on March 8.
The items were seen in one of the remotest parts of the globe where the icy waters are sometimes 9800 feet deep, and 1500 miles off the Perth coast.
Their location roughly corresponds to the far end of a southern track that investigators calculated the aircraft could have taken after it was diverted shortly after take-off and its tracking systems were knocked out.
A Norwegian merchant ship has arrived in the area but there is no confirmation yet the objects belonged to the plane.
The items may have drifted far from any crash site.
Malaysian Transport Minister Hishammuddin Hussein said: "I said that we wanted to reduce the area of the search. We now have a credible lead."
A Royal Navy vessel was due at the scene along with a vessels from the Australian, US and New Zealand navies.
Mr Hishammuddin said the information on the objects received from Australia had been "corroborated to a certain extent" by other satellites, making it more credible than previous leads.
Merchant navy captain Bimal Sharma, whose sister Chandrika is among the passengers, talked of his feelings of "hope and then despair and then hope and then despair".
He said that he does not want to believe the debris belongs to the plane, adding: "I have been through that area several times.
"This area has got a concentration of garbage, plastics and wood."