Malaysia MH370: Australia says cost 'no issue'
Australia has said it will not abandon the search for the missing Malaysia Airlines plane, insisting that the cost of the operation is not a concern.
PM Tony Abbott said if the current underwater search was unsuccessful, a new strategy would begin.
Defence Minister David Johnston has said that powerful sonar equipment will probably be used in the next stage.
The plane was carrying 239 people from Kuala Lumpur to Beijing when it disappeared in March.
A US Navy Bluefin-21 mini-submarine scanning the ocean bed has covered more than 80% of a 310 sq km (120 sq mile) search area in the southern Indian Ocean, without finding any sign of debris in water that is up to 4.5km deep.
Mr Abbott said the probable impact zone of the airliner was in an area of the sea floor 700km (430 miles) long and 80km (50 miles) wide.
In a separate development, Malaysian Transport Minister Hishammuddin Hussein said that his country's cabinet had approved the formation of an international investigation team to find out what happened to the missing plane.
"The main purpose of the team is to evaluate, investigate and determine the actual cause of the accident so similar accidents could be avoided in the future," he told reporters in Kuala Lumpur.
Australia says that it is now consulting with Malaysia, China and the United States on the next phase of the search, which is likely to be announced next week.
Mr Abbott said a new search strategy would be put into action if nothing was found in the current seabed search.
"If at the end of that period we find nothing, we are not going to abandon the search, we may well rethink the search, but we will not rest until we have done everything we can to solve this mystery," he said.
"We owe it to the families of the 239 people on board, we owe it to the hundreds of millions - indeed billions - of people who travel by air to try to get to the bottom of this."
Up to 10 military aircraft and 12 ships are currently searching about 1,600km (990 miles) north-west of Perth. The daily operation, involving some two dozen nations, is already shaping up to be the most expensive in aviation history.
"The only way we can get to the bottom of this is to keep searching the probable impact zone until we find something or until we have searched it as thoroughly as human ingenuity allows at this time," the Australian prime minister said.
The defence minister said that searchers were now planning to use a more intensive sonar to intensify the hunt for the aircraft.
"The next phase, I think, is that we step up with potentially a more powerful, more capable side-scan sonar to do deeper water," Mr Johnston said.
"There will be some issues of costs into the future but this is not about costs."
The commercial sonar equipment being considered is similar to the remote-controlled submarines that found the wreck of the Titanic 3,800m (12,500ft) under the Atlantic Ocean in 1985.
"We want to find this aircraft. We want to say to our friends in Malaysia and China this is not about cost, we are concerned to be seen to be helping them in a most tragic circumstance," Mr Johnston said.
The enthusiasm and commitment of search teams had not dimmed, he added, despite the complexity of the operation in one of the most isolated parts of the Indian Ocean.
Authorities still do not know why the plane flew so far off course and finding the plane's flight recorders is seen as key to understanding what happened.
Using satellite data, officials have concluded that MH370 ended its journey in the southern Indian Ocean.