The next phase of the hunt for missing Malaysian jet MH370 will move hundreds of miles south, officials have said.

The search will focus on an area 1,800km (1,100 miles) off the city of Perth, Australian Transport Safety Bureau (ATSB) chief Martin Dolan said.

Nearby areas were previously surveyed from the air, but the undersea hunt was directed north after pings were heard.

The jet vanished en route from Kuala Lumpur to Malaysia on 8 March with 239 passengers on board.

Experts had hoped that the pings detected shortly after the plane vanished were from its flight-data recorders.

But after weeks of searching the ocean floor, it was concluded that the noises were unrelated to the plane.

Painstaking mapping

Search teams have now returned to the initial satellite data to frame the new search area.

"All the trends of this analysis will move the search area south of where it was," Mr Dolan said.

"Just how much south is something that we're still working on."

He said it was unlikely that the new search area would be as far from land as the aerial surveys had been.

Before search teams can start looking for the plane, the seabed will be mapped.

A Dutch firm has been contracted to carry out a detailed survey of the ocean floor.

The sea in the area is 6km deep, and the analysis is expected to take three months.

Many of the relatives of the missing passengers have been frustrated by the lack of progress in the search.

Crews have not been able to find a trace of the plane.

(BBC)