Australian authorities are "clutching at whatever little piece of information comes along" in the search for missing Malaysia Airlines flight MH370, Deputy Prime Minister Warren Truss said Monday.

Truss was speaking to ABC's Radio National after the Australian Maritime Safety Authority announced the total search area in the southern Indian Ocean had been expanded to 68,500 square km Monday from 59,000 square km the day before.

"Certainly the areas where debris has been picked up by satellites is of particular interest, and they're the focus of a lot of the searching," Truss said.

Searchers are now looking for objects spotted in three sets of satellite photos: U.S. images taken on March 16, Chinese images taken two days later and French images, which were still being studied, that emerged on Sunday.

They are also trying to find a wooden pallet, packing straps and other unidentified objects that were spotted from an aircraft on Saturday.

"The French sighting is a piece of new material because that is in a completely different location. That is about 850 kilometers north of our current search area," Truss told Radio National.

"So we need to check that out as well."

Malaysia's Transport Ministry had said the French images showed "floating debris", but gave no details of the number, size or precise location of the objects, said the report.

Truss said the debris in the French images was not in an area authorities had identified as the most likely place where the aircraft may have entered the sea.

"We still don't know for certain that the aircraft is even in this area," he said.

"We are just clutching at whatever little piece of information comes along to try and find a place where we might be able to concentrate the efforts."

He also said Tropical Cyclone Gillian, near Christmas Island, could bring bad weather south, hindering search efforts.

"It is a very difficult task. The weather yesterday wasn't too bad, although there was early morning fog," he said.

"Today we expect the weather to deteriorate and of course the forecasts ahead are not all that good.

"So it's going to be a challenge but we'll stick at it."

The pilot of one of the Royal Australia Air Force Orions involved in the search told Radio National that conditions had been challenging.

Flight Lieutenant Russell Adams said there had been heavy cloud cover and his crew was not able to spot any debris.

"We're going out there for two, three hours at a time, so the satellite imagery is going through the center and we've been tasked appropriately through them," he said.

Seven military aircraft -- two from China, two from Australia, two from Japan and one from the U.S. -- and three civil aircraft are taking part in Monday's search covering two areas in close proximity about 2,500 km from the southwestern Australia city of Perth.?