The search off the Australian coast for debris spotted in an area about 2500 southwest of Perth turned up no sightings of significance on Sunday.

Early fog was an issue, particularly in western areas of the split 59,000 square kilometre search area, but conditions had started to improve later in the day, according to AMSA.

RAAF Flight Lieutenant Russell Adams said heavy cloud cover reduced his crew's ability to see the ocean from their P3-Orion.

At times the plane had been "completely" engulfed in cloud, even at its lowest altitude, he said.

Australian search authorities have previously said the human eye, rather than onboard technology, was likely going to be the tool to find debris from the air.

"There are other aircraft out there searching other areas who were getting better visibility," Captain Adams said.

Fellow Australian pilot Flying Officer Peter Moore, who captained another Australian military aircraft involved in the search also described challenging conditions.

"Weather conditions out in the search area today were again less than favourable," he said. "The search area we were assigned today, we had again low cloud... and in the majority of the area we had a lot of sea fog and showers extending down to the ocean surface.

"Search conditions were quite trying today, we did however, have some extra fuel up our sleeves and we were able to cover parts of the area that we couldn't cover in the earlier part due to weather.'

Captain Adams said flight crews were working directly with the rescue coordination centre in Australia and were "being tasked appropriately" based on information, including satellite imagery as it became available to Australian authorities.

The Australian flight crews had landed on the tarmac at RAAF Pearce on the outskirts of Perth hours after a French satellite revealed promising new images of objects in the Australian search zone.

The latest discovery comes a week after satellites first captured an image of two large pieces of debris floating in waters within the Australian search and rescue zone; and three days into the search.

Captain Adams said flight crews remained committed to assisting in what has become an international air search effort.

"We do search and rescue quite regularly when called upon and we might do ten sorties and find nothing, but on that eleventh flight when you find something and you know that you're actually contributing to some answers for somebody," he said.

"We've still got the drive and we're still really keen that we can continue to contribute to the effort."

Captain Moore later said: "We're quite experienced in search and rescue operations and I can confidently say on behalf of my crew and myself that we're at least going to try and achieve some answers for the family and friends of the flight MH370."

On Saturday acting Prime Minister Warren Truss had said the Australian search would continue indefinitely, with no contingency in place or an end in sight "as long as there's hope."

The Southern Indian Ocean images were the world's most credible lead in the hunt for missing Malaysia Airlines flight MH370, Mr Truss said.

The search is due to resume on Monday with the addition of Chinese military Ilyushin IL-76 planes and Japanese P-3Cs.