Up to eight aircraft and nine ships will be involved Thursday in the hunt for missing Malaysian airliner MH370 and the search area will be adjusted to move further north, retired Air Chief Marshal Angus Houston said.

While briefing visiting Malaysian Prime Minister Najib Razak about the international search effort in RAAF Base Pearce, Houston said that Australia is doing everything it can to assist Malaysia to find MH370 and to recover what they can from the Indian Ocean.

"It is the most challenging and demanding search and recovery operations I've seen and probably one of the most complex operations of this nature the world has seen," said Houston, who heads the Joint Agency Coordination Center (JACC) coordinating the operation.

Najib also met with his Australian counterpart Tony Abbott at the base near the west coast city of Perth.

The eight planes and nine ships will scour an area of about 223, 000 square km, 1,680 km west north-west of Perth on Thursday.

The weather is forecast to be fair, with visibility of approximately 10 km despite some isolated showers in the southern area.

British submarine HMS Tireless and HMS Echo have arrived in the southern Indian Ocean to assist in the search for the plane and the "black box" flight recorders.

An Australian E-7A Wedgetail aircraft capable of deconflicting air space in the search area also assisted in the mission which has dragged on for more than three weeks but turned out to be fruitless as yet.

The Australian Transport Safety Bureau (ATSB) refined the area where the aircraft entered the water based on continuing ground- breaking and multi-disciplinary technical analysis of satellite communication and aircraft performance.