The drawn-out search for missing Malaysian Flight MH370 will revert to an area south of the previously suspected crash site following new analysis of the plane's flight path, an official said Friday.

Investigators grappling to solve the mystery of the jet's disappearance are reportedly set to scour a zone 1,800 kilometres (1,100 miles) west of Perth -- previously subject to an aerial search -- when an underwater probe resumes in August.

The Australian Transport Safety Bureau, which is leading the search, would not pinpoint the exact location of the probe as analysis is still ongoing, but said it was clearly further south.

"It is already clear from the provisional results of our analysis that the search zone will be south of the previous search area," a bureau spokesman told AFP.

"But still on the seventh arc where the aircraft last communicated with the satellite."

Australian officials have said repeatedly that the revised search zone will be in the area of the seventh arc, or the final satellite "handshake" from the plane. It is believed to be when the aircraft ran out of fuel and was in descent.

Citing unnamed US sources, The West Australian newspaper said Friday that Australia's Joint Agency Coordination Centre (JACC) would soon announce the hunt would move 800 kilometres southwest from where it was previously focused.

It said sources had revealed that survey ship Fugro Equator was already operating in this area and would soon be joined by Chinese vessel Zhu Kezhen.

- No sign of plane -

A massive aerial and underwater search for MH370, which had 239 people onboard when it diverted from its Kuala Lumpur to Beijing flight path on March 8, has failed to find any sign of the plane.

Scientists from British satellite operator Inmarsat told the BBC earlier this week that the search had yet to target the most likely crash site, or "hotspot", after becoming diverted by pings thought at the time to have originated from the plane's black boxes.

It was not clear from The West Australian report whether the new search area overlaps with the "hotspot".

Until now, the most intensive search had been with a mini-sub in the area where the pings were detected. The area has now been ruled out as the final resting place of MH370. The source of the noises is unknown.

JACC said Friday that the revised search zone, based on an intensive study of satellite communications from the jet and other data, would be announced by the end of the month.

It said the Fugro Equator was now working in this zone.

"Located along the seventh arc, that area is consistent with provisional analysis of satellite and other data that is being used to determine the future search area," it said.

Australian officials announced earlier this week that a survey of the sea bed, as yet mostly unmapped and crucial to the success of the underwater search, had resumed.

The two ships -- Fugro Equator and Zhu Kezhen -- will survey an area up to 6,000 metres (20,000 feet) deep and covering up to 60,000 square kilometres before an a contractor begins an intensive undersea probe looking for debris.