China, US spending

The other big spenders so far are China and the United States.

China, which was home to the majority of the 227 passengers on board the missing plane, has sent a total of 18 ships, eight helicopters and three fixed-wing aircraft to various search areas during the month-long hunt.

China has been sending two Ilyushin Il-76 aircraft, on alternate days, on sorties from RAAF Pearce Base near Perth for almost three weeks. The Global Times, a tabloid published by the People's Daily, estimated that an Ilyushin Il-76 costs $10,000 an hour to keep in the air on fuel alone, not including money spent on maintenance or accommodation for the crews.

Chinese warships would cost at least $100,000 a day to operate, and most likely a lot more, the newspaper added.

The Pentagon said last week that it had already spent more than $3.3 million on the search and has put in place plans to nearly double its original $4 million budget.

As well as flying its P-8 surveillance planes out of Perth, the US Navy is playing an instrumental role via its high-tech underwater black-box detector equipment.

It has sent both its Towed Pinger Locator, which this week picked up signals which may be from the missing plane's cockpit data recorders, and a Bluefin-21 autonomous underwater vehicle.

An earlier search in the South China Sea by Vietnam was estimated by local media to cost $8 million, a figure that has not been verified by officials.

($1 = 1.0759 Australian Dollars) ($1 = 0.7303 Euros)