Australian ship Ocean Shield detected two more suspicious signals in an intensified search for missing Malaysia Airlines flight MH370, the Australian coordination chief said at a press conference on Wednesday.

"Ocean Shield has been able to reacquire the signals on two more occasions, late yesterday afternoon and later last night," said Angus Houston, head of Australia's Joint Agency Coordination Center (JACC).

Although the last signal heard was weak, the new detections boosted the hope that "we are searching in the right area," which is approximately 2200 kilometers northwest of Perth, said Houston.

Ocean Shield, equipped with U.S.-supplied towed pinger locater, heard two suspicious pulse signals on Monday.

On Saturday and Sunday, the towed-pinger locator deployed from Ocean Shield also detected signals consistent with those emitted from aircraft black boxes at separate locations.

Houston said data analysis of the first two signals, detected on April 5 at 4.45pm and at 9.27pm Perth time, confirmed that they were consistent with aircraft black boxes and not from a natural origin.

Experts "believe the signals to be consistent with the specification and description of a flight data recorder," Houston told reporters.

Though the new detections were "great lead," Houston cautioned that there is still a long way to go and no final conclusion can be made until "somebody sees the wreckage."

He said the U.S. underwater vehicle will not be sent down to scour the ocean floor until all possibilities of surface search are exhausted.

11 military aircraft, four civil aircraft and 14 ships were sent to search for missing Malaysia Airlines flight MH370, said the Joint Agency Coordination Center (JACC) for the international search efforts in a statement on Wednesday.

AMSA's planned search area for?Wednesday is about 75,423 square kilometers and the centre of the search area is approximately 2261 kilometres north west of Perth, said the JACC statement.

The Boeing 777-200 aircraft carrying 227 passengers, including 154 Chinese, and 12 crew members disappeared on March 8 while flying from Kuala Lumpur to Beijing.

Since then, China, along with more than 20 other countries, has joined the unprecedented international search for the plane.

But so far no definitive signs of the plane have been found yet.

(Xinhua contributed to the story)