Australia investigating possible debris from MH370 in Indian Ocean off Perth

Australian search and rescue efforts were redirected on Thursday to a location some 2,500 kilometres south-west of Perth after satellite images emerged of what experts deemed to be "credible" sightings of debris of the missing Malaysia Airlines flight MH370.

But Australian officials stressed that it was not confirmed if the debris was related to MH370.

Two objects, the larger of which was measured at 24 metres, were found floating in the Indian Ocean, Australian officials said.

"The objects are relatively indistinct. The indication to me is of objects that are of a reasonable size and probably awash with water and bobbing up and down over the surface," Australian Maritime Safety Authority official John Young told a press briefing in Canberra.

"The largest... was assessed as being 24 metres. There is another one that is smaller than that."

Australia has sent four search aircraft - including one each from the US and New Zealand - and two ships to the area where the debris was located while another merchant ship has also been asked to go there. It takes four hours for an aircraft flying out of base in Perth to reach the location.

Water in the search area may be "several thousand metres deep" and poor visibility in the area would hamper the search, although the weather was moderate, Mr Young said.

The satellite images were progressively captured by satellites passing over the region and were only made available on Thursday morning, according to a top defence official. The assessment of these images was provided by the Australian Geospatial-Intelligence Organisation.

Mr Young said further images were expected to be provided "in due course" after commercial satellites were redirected to take high-resolution images of the areas of interest.

Mr Young emphasised that there was no guarantee that the images were indeed debris floating in the ocean. Containers, for example, are sometimes adrift after falling overboard.

It is not known when the objects will be physically located.

Mr Young told reporters: “There are many steps to happen before we get to that point (getting any single piece out of the water).”

“What we are looking for is a confirmation that it does belong to the aircraft, or it does not. We may get a sighting, we may not. We may get it tomorrow, we may not.”

Prime Minister Tony Abbott warned against drawing any premature conclusions.

"We must keep 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 told parliament earlier on Thursday.

The Boeing 777-200 Malaysia Airlines plane vanished in the early hours of March 8 after veering drastically off course over the South China Sea while en route to Beijing.

Sketchy radar and satellite data resulted in investigators proposing two vast search corridors, stretching south into the Indian Ocean and north over South and Central Asia. Many analysts now favour the maritime southern corridor, pointing out the unlikelihood of the airliner passing undetected over nearly a dozen countries.

The international search has been marked by numerous false leads thus far.

Mr Young characterised the satellite imagery as the "best lead" Australia  had now.

He said: "This is a lead, it is probably the best lead we have right now. But we need to get there, find them, see them, assess them, to know whether it's really meaningful or not."