The new theory, reported in Malaysia's pro-government New Straits Times, came as Australia took over search and rescue operations in the southern Indian Ocean after a request to Prime Minister Tony Abbott from his Malaysian counterpart, Najib Razak.

In a bombshell announcement on Saturday, Mr Najib announced that satellite data showed MH370 flew for more than seven hours, identifying two possible routes it took - north-west across Thailand, China and towards northern Iran; or south-west across Indonesia and down into the southern Indian Ocean, about 1000 kilometres from the coast of Western Australia.

The north-west route would have taken the plane across numerous countries where civilian and military radar was located, as well as a heavy presence of satellite surveillance, yet there has been no evidence to date that it was detected in the air or on land some nine days after it disappeared.

According to the New Straits Times, investigators are poring over MH370's flight profile to determine if it had flown low and used ''terrain masking'' during its flight to avoid radar detection.

It could also have taken advantage of busy commercial routes, meaning the flight may not have raised the suspicion of those manning military radars in the nations it flew over. It would have appeared to be just another commercial aircraft on its way to its destination, the paper said, quoting unnamed ''top officials''.

''While the ongoing search is divided into two massive areas, the data that the investigating team is collating is leading us more towards the north,'' the sources told the paper.

The plane's captain, Zaharie Ahmad Shah, was a highly experienced pilot with a passion for flight simulators, one of which he kept in his home. But Malaysian police say they have examined his home simulator and found nothing unusual. Moreover, there was no evidence the grandfather had any links to militant groups.

It also emerged that the last communication from the cockpit by an unknown person - ''all right, good night'' - was made after the plane's transponders had been deliberately shut down, supporting other evidence that the flight was hijacked or sabotaged.

However, the southern route also remains an active source of investigation.

Mr Abbott told Parliament on Monday afternoon that Australia would co-ordinate operations in the vast search area to its west.

He said he has no firm information to back claims that the missing plane may have travelled south towards Australia.

''But all of our agencies that could possibly help in this area are scouring their data to see if there's anything that they can add to the understanding of this mystery,'' Mr Abbott said.

Australia's powerful Jindalee radar network had the capability to detect the plane if it followed the southern route identified by investigators, Australian National University surveillance specialist Des Ball said.

However, Defence sources said it had not picked up any information suggesting the plane had flown south and the Jindalee radar may not have been directed towards the right area at the right time.

Professor Ball said the Inmarsat satellite that picked up six ''pings'' from MH370 would not have been able to identify routes anyway.

''The arc on that map simply tells you that the aircraft was somewhere in that circle, nothing about its position or direction of flight,'' he said.

He added that an experienced pilot flying low, and with knowledge of the location of military radar, could conceivably have flown the plane across Asia without detection.

Australia has two P-3 Orion surveillance planes contributing to the search. It is understood that a further contribution would consist of more Orion aircraft, as these are the best-suited military assets Australia has for the job.

If one of the planes spots wreckage or some other sign of the Malaysian aircraft, a navy frigate would be deployed to investigate more closely.

If flight MH370 took a south-west path, then it would have most likely have gone into Australia's search and rescue zone, which stretches thousands of kilometres into the Indian Ocean, extending about halfway to southern Africa.