It's a race against time to find the black box of the missing Malaysia Airlines jet before the flight recorder's batteries run out in the next few hours.

This Chinese search vessel is trying to trace signals emitted by the recorder before it goes silent.

Haixun 01, briefly reported hearing signals over the weekend in this remote part of the southern Indian Ocean.

But while the investigation here continues, an Australian vessel has detected signals in another search area more than 1,500 km west of Perth.

(SOUNDBITE) (English) CHIEF COORDINATOR OF THE JOINT AGENCY COORDINATION CENTRE (JACC), ANGUS HOUSTON, SAYING:

"The towed pinger locator deployed from the Australian defence vessel 'Ocean Shield' has detected signals consistent with those emitted by aircraft black boxes. Two separate signal detections have occurred within the northern part of the defined search area."

Air Chief Marshal Angus Houston, who is leading the search, said the information mus