Two separate signals have been detected by a US pinger locator being towed by the Australian Defence Vessel Ocean Shield in the Indian Ocean search area, about 1,700 km northwest of Pert, WA Today reported.
Up to 12 aircraft, nine military and three civilian, and 14 ships were scheduled to assist in the southern Indian Ocean search on Monday.
If another signal is detected, a Bluefin-21 autonomous underwater vehicle equipped with sonar and an underwater camera would be dropped to the ocean floor to search for wreckage.
"The towed pinger locator deployed from the Australian Defence Vessel Ocean Shield has detected signals consistent with those emitted from aircraft black boxes," said Angus Houston who is heading the Joint Agency Coordination Center (JACC).
"Their work has enabled us to come up with an underwater search area which is quite narrowly focused and with the acoustic events that we're getting in the area, we're encouraged that we're very close to where we need to be," Houston said.
The first detection of the signal was found early on Sunday, which lasted for two hours and 20 minutes. After few hours, the second signal was detected which lasted for 13 minutes.
The two signals were about 1800 metres apart and might have been from a single or two separate sources, said Commodore Peter Leavy, the man in charge of the search.
Commodore Leavy added that finding the origins of the signals would be of a slow process as the sound waves under water can distort by 90 degrees or more.
"It is a markedly different environment to what you see with sound travelling through air," he said.
The ADV Ocean Shield would continue to take rounds around the 1800-metre detection zone to re-locate another signal in the next 24 hours.
The ADV Ocean Shield detection on Sunday came shortly after a Chinese patrol vessel, the Haixun One Zero, reported detecting two pulse signals on Friday night, and then again Saturday at a frequency consistent with black box technology.
The ships are within a search area more than 300 nautical miles long, with the ADV Ocean Shield at the northern end and the Haixun Zero One at the southern end.
Both ships are within the range where the missing jet was most likely to have entered the water.
The HMS Echo and a Royal Australian Air Force (RAAF) aircraft were diverted to the Haixun's location on Sunday in a bid to verify whether the detections were linked to the missing plane's black box.
Search crews are extremely worried about the fact that the batteries powering the black boxes' signals were already past their minimum lifespan.
Malaysia Airlines flight MH370 vanished mysteriously about an hour after taking off from Kuala Lumpur shortly after midnight March 8.
The Boeing 777-200ER was scheduled to land in Beijing the same day. The 227 passengers on board included five Indians, 154 Chinese and 38 Malaysians.
Despite extensive scouring of the remote southern Indian Ocean area by planes and ships off the coast of Perth, where the plane is believed to have crashed, no trace has been found.