CANBERRA, April 28 -- The new technology of towed side- sonar device will be deployed in four weeks, Angus Houston, chief coordinator of the Joint Agency Coordination Center (JACC) for the search of Malaysian Airline flight MH370, said here Monday.

At a press conference held in the Chinese Embassy in Australia, Houston said the towed side-sonar search would be conducted by possible private underwater search and recovery companies.

The device will work just above ocean floor, exactly as the Bluefin-21 Autonomous Underwater Vehicle does, to get maximum value from side-looking sonar.

"It had a wide cut than Bluefin. It travels along at quite a slow pace of about 4 to 6 knots. So it doesn't go very fast, but it's in the water all the time, providing a live image of the ocean floor all the time."

The only time it won't be able to do is when it turns the whole system around. It takes the device half a day to turn and change direction.

As was the case with visual search both by air and at sea, anything underwater will be de-conflicted so that there will be no conflict between one system or another.

"They will be coordinated so they will be separated," he said.

"In terms of how the ocean floor is covered, it will coordinate to do it in the most efficient and effective manner."

Houston said it's important to keep the continuity and momentum when the search has entered the new phase, during which four vessels from China, Malaysia and Australia will be involved and an Australian P-3 C Orion aircraft will be put in standby in timely response to any sighting by commercial or fishing vessels of possible debris.