DHAKA: A mini-sub hunting for missing Malaysia Airlines Flight MH370 will be back in the search zone within days, an official said on Saturday, as the Australian ship carrying the device prepared to leave on the mission.

Australian vessel Ocean Shield is carrying the US Navy Bluefin-21 mini-sub which had been scouring the seabed for the plane until it docked to resupply early this week.

Ocean Shield is due to head back on Saturday to the remote area of the Indian Ocean where transmissions believed to have come from the plane's black box recorders were heard last month.

It will take the vessel three days to reach the location.

Once in the area, Ocean Shield will be able to deploy the Bluefin-21 to look for ‘any non-normal items, any metallic items’, US Navy Captain Mark Matthews told the Australian Broadcasting Corporation, reports The Straits Times.

‘They’ll either find something or they won’t, that’s about all I can box in, but what you do is you go look at your best indications and you pursue them until they’re exhausted,’ he said.

Captain Matthews said it was impossible to know for sure whether the signals picked up were from the plane’s black box.

‘It is certainly a man-made signal, but what it’s from, I can’t look at it and positively say, ‘Hey that’s an underwater locator beacon’,’ he said.

Flight MH370, carrying 239 people, disappeared on March 8 while travelling from Kuala Lumpur to Beijing.

Extensive air and sea searches over vast stretches of the Indian Ocean have failed to find any sign of the plane.

BDST: 1820 HRS, MAY 10, 2014