The Australian Maritime Safety Authority on Thursday received an expert assessment of commercial satellite images possibly related to the search for MH370
It showed potential debris in an area 2500 kilometres south-west of Perth
A RAAF Orion arrived on the scene at 1.50pm AEDT.
An additional three aircraft have been sent to the area, including a New Zealand Air Force Orion and a US Navy P8 Poseidon aircraft.
The US Navy P8 Poseidon aircraft arrived at 3pm and the second RAAF Orion is expected to depart RAAF Base Pearce, north of Perth, at 6pm.
The New Zealand Air Force Orion, is due to depart at 8pm.
FROM THE PRESS CONFERENCE:
The press conference has been told that it is not uncommon to find debris in the ocean. It can be containers from ships falling overboard, for example.
But the size and the fact that a number of objects were located in one area give credence to the idea it may be debris from MH370, AMSA says.
The satellite images are credible enough to divert the search to this area, authorities have said.
Weather conditions are moderate in the southern Indian Ocean, but visibility is poor.
However, they have reminded reporters that this is still no guarantee the objects in question are the plane.
The largest piece of debris spotted is up to 24 metres long.
"The indication are of objects that are a reasonable size and are possibly awash, with water going up and down over the surface," John Young.
Apparently the possible debris has been spotted approximately 2500 kilometres south-west of Perth, according to AMSA.
AMSA says in its latest statement that the Australian Geospatial Intelligence Organisation - Defence's satellite experts - have assessed the satellite images as "a possible indication of debris".
EARLIER: The Australian-led search for the missing Malaysian Airlines flight has had an apparent breakthrough, with satellite images showing two objects in waters off Perth.
Prime Minister Tony Abbott told Parliament on Thursday afternoon that an Australian P-3 Orion aircraft had been diverted to check out the objects and would be followed by other planes.
The first Orion was due to arrive on the scene about 2pm, he said.
Mr Abbott stressed it was not yet clear whether they were parts of the plane.
But Mr Abbott described the breakthrough as "new and credible information."
"The Australian Maritime Safety Authority has received information based on satellite imagery of objects possibly related to the search," Mr Abbott said.
"Following specialist analysis of this satellite imagery, two possible objects related to the search have been identified."
"I should tell the House - and we must keep this in mind - the task of locating these objects will be extremely difficult and it may turn out that they are not related to the search for flight MH370," Mr Abbott said.
"Nevertheless, I did want to update the House on this potentially important development.’’
Mr Abbott said he had informed his Malaysian counterpart, Prime Minister Najib Razak, and promised to keep him updated.
The Australian Maritime Safety Authority, which is co-ordinating the search, has called a news conference for 3.30pm.