An intensified underwater search for missing Malaysia Airlines Flight MH370 will start in about two weeks' time, Australian premier Tony Abbott said Saturday as he visited Malaysia to discuss the issue.

Abbott said the hunt for the jet, which inexplicably veered off its Kuala Lumpur-Beijing route on March 8 with 239 people aboard, would continue for as long as necessary.

Australia has been spearheading the hunt for the plane, which is believed to have crashed in the southern Indian Ocean off western Australia, but the massive air, sea and underwater search has so far failed to find any wreckage.

Speaking after talks with his Malaysian counterpart Najib Razak, Abbot said the new phase of the search would begin "in about a fortnight's time", in addition to ongoing mapping through a sonar survey.

"(The underwater search) will utilise the best available technology. It will last as long as it needs to scour the seabed," he told reporters.

Experts have used technical data to finalise MH370's most likely resting place deep under the Indian Ocean.

The more intense underwater search will focus on a dauntingly vast stretch of ocean measuring 60,000 square kilometres (23,000 square miles).

Najib's government and the national flag carrier were widely criticised over what many saw as a disorganised and secretive response to MH370's disappearance.

- 'Justice' for MH17 -

Paying his first official visit to Malaysia, Abbot also discussed with Najib the fate of Malaysia Airlines Flight MH17, which exploded over strife-torn eastern Ukraine in July.

The two leaders called for "justice" for the 289 people -- among them 38 Australian citizens or residents -- who were killed in the disaster.

The West has blamed Russian-backed separatists for shooting down the plane, while Moscow blames Kiev.

Najib said intelligence reports on what happened to the plane were "pretty conclusive" but did not elaborate.

Dutch air crash investigators have announced that they will release a preliminary report on Tuesday into what brought down the flight, travelling from Amsterdam to Kuala Lumpur.

The Netherlands is leading the probe into the crash, which killed 193 Dutch citizens.

"What we need to do next is to assemble physical evidence that can be brought to court when the time comes so that it will be proven beyond any doubt that the plane was shot down," Najib said.

He added investigators needed "at least a few weeks" -- before winter set in -- to search the crash site for human remains and to "assemble physical evidence".

The search has been suspended since early August due to heavy fighting between Kiev and pro-Moscow rebels in the area and although most human remains have been recovered, some are believed to still be at the site.

"Once that process is completed, we will look at the criminal side, who is responsible for this atrocious crime," he said.

The two premiers also met with Malaysian personnel involved in the missions to find MH370 and to salvage wreckage and remains from the MH17 crash site.

Later in the day, Abbott will meet business leaders as well as educationalists to present his government's "New Colombo Plan", a scholarship programme to encourage more Australians to study across the Indo-Pacific region, officials said.