The search and and rescue team in Perth, will be deploying a mini-sub, the Bluefin-21, into the Indian Ocean as soon as possible, to determine whether the acoustic signals detected in the area are indeed related to MH370's black box.

Joint Agency Coordination Centre (JACC) head Angus Houston said Ocean Shield will cease searching with the towed pinger locator later today before Bluefin-21 could be deployed soonest.

"We haven't had a single detection in six days so I guess it's time to go underwater," he said at a press conference in Perth today.

Houston said the analysis of the four signals detected earlier, has allowed the provisional definition of a reduced and managable search area on the ocean floor.

"The Bluefin-21 is equipped with side scan sonar. Once deployed, it will begin searching the sea floor in the vicinity of the detective signals.

"Each mission conducted by the Bluefin-21 will take a minimum of 24 hours to complete.

"It will take two hours to get down to the bottom of the ocean, it will be on task 16 hours, it will take two hours to surface and four hours to download and analyze the data collected.

"The autonomous underwater vehicle in side scan sonar mode, transmits an active pulse which produces high resolution, three dimensional map of the sea floor," he said.

Houston said Bluefin-21's first mission will cover an area of five kilometers by eight kilometers, an area of 40 sq km.

"The deployment of the autonomous underwater vehicle has the potential to take us a further step towards visual identification since it offers a possible opportunity to detect debris from the aircraft on the ocean floor," he said.

Houston however cautioned that aircraft wreckage has to be visually identified before they can say with certainly that that is the final resting place of MH370.

"It may not," he said.

Before this, Houston said the search and rescue team said it will not deploy submersibles onto the seabed unless another transmission is received.