PARIS (AFP) -- Europe's aviation safety watchdog called Tuesday for the transmission time of tracking beacons fitted onto black box flight recorders to be extended from 30 to 90 days, a reform that may have made it easier to find the missing Malaysia Airlines plane.

The aircraft disappeared on March 8 with 239 people on board, and an intense search for the plane has been scaled back after coming up with nothing despite an air and sea hunt over 4.64 million square kilometres of the southern Indian Ocean.

Part of the problem is that the batteries to the beacons fitted onto the so-called "black box" cockpit voice recorder and flight data recorder -- which are crucial in locating a plane and determining what caused it to crash -- have died, making the search even more difficult.

In a statement, the European Aviation Safety Agency urged "the extension of the transmission time of underwater locating devices fitted on flight recorders from 30 days to 90 days".

The agency suggested that all large planes flying over oceans be equipped with a new type of ULD with a longer locating range.

The minimum recording duration of cockpit voice recorders installed on new large planes should also be increased to 20 hours from the current two hours, it added.

"The tragic flight of Malaysia Airlines MH370 demonstrates that safety can never be taken for granted," said Patrick Ky, EASA's director.

"The proposed changes are expected to increase safety by facilitating the recovery of information by safety investigation authorities."

The recommendations need to be adopted by the European Commission, and will apply to all planes and helicopters registered in the 32 EASA member states.

Australia on Monday hosted a meeting in Canberra with the transport ministers of Malaysia and China to determine the way forward in the hunt for the missing plane, which will focus on an intensified undersea search.

China is involved because two-thirds of the passengers were Chinese, while the plane is believed to have gone down in Australia's search and rescue territory.

Australian Deputy Prime Minister Warren Truss admitted the hunt will take time, with the ocean bed in the prospective search zone several kilometres deep and largely unmapped, meaning specialist sonar equipment and other autonomous vehicles are needed.

He said a tender process would start soon to acquire them, but it would likely be two months before the equipment was actually in the water, while more oceanographic mapping was required to better understand where they would be looking.

A submersible Bluefin-21 has been scouring the seabed in an area where undersea transmissions were detected, believed to have come from the plane's black box flight recorders before the batteries died.

It will soon be joined by a dedicated team of vessels from Australia, Malaysia and China. An Australian P-3 Orion jet will also be available to follow up any leads.