PERTH -- Up to 11 military planes, four civil planes and 14 ships will assist in Wednesday's search for the missing Malaysian flight MH370, the Joint Agency Coordination Center (JACC) for the international search efforts said in a media release.

The search area is expected to be about 75,423 square km, with its center some 2,261 km north west of Perth.

A weak front is moving in from the southeast, expected to bring scattered showers.

The underwater search continues today, with ADV Ocean Shield at the northern end of the defined search area, and Chinese ship Haixun 01 and British HMS Echo at the southern end, said the JACC.

A Chinese IL-76 transport aircraft took off at about 6:00 local time (22:00GMT Tuesday) from the Perth International Airport to conduct searching in an area about 2,000 km to Perth, said a press liaison official with China's embassy to Australia.

The Australian Transport Safety Bureau continues to refine the area where the aircraft entered the water based on continuing ground-breaking and multi-disciplinary technical analysis of satellite communication and aircraft performance, passed from the international air crash investigative team comprising analysts from Malaysia, the United States, Britain, China and Australia.