A US submarine drone will keep scouring the Indian Ocean floor for traces of a missing Malaysian jetliner after it finishes its targeted search, Australian authorities said as a tropical cyclone suspended the air search.

Authorities are under growing pressure to decide their next course of action as the Bluefin-21 drone nears the end of its first sweep of remote seabed which authorities believe is the most likely resting place of Malaysian Airlines flight MH370 which vanished on March 8 with 239 people on board.

The Bluefin-21 is expected to finish its targeted search of a 10 square kms (6.2 sq mile) stretch of ocean floor, where a signal suspected to be from the plane's black box was detected, today. No wreckage has been found.

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"Bluefin-21 has now completed more than 80% of the focused underwater search area and further missions are planned," the Perth based Joint Agency Coordination Centre said.

"The search will continue. We are consulting very closely with our international partners on the best way to effect this for the future."

As the Bluefin embarked on its 10th trip to depths of more than 4.5km (2.8 miles), a tropical cyclone suspended the air search.

Daily sorties have continued unabated in what is shaping to be the most expensive search in aviation history.

"There will be no change to our mission of one nine-hour flight per day," US 7th Fleet public affairs officer Commander William J. Marks said yesterday.