KUALA LUMPUR (THE STAR/ASIA NEWS NETWORK) - Malaysian Prime Minister Datuk Seri Najib Razak extended his "heartfelt condolences" to families and loved ones of victims aboard the Indonesia AirAsia flight QZ8501, which went missing over Indonesian waters two days ago.

"I hope that search efforts continue in case of survivors. If there are no survivors, I hope that families stay strong in this trying time," Mr Najib said on Tuesday.

The Airbus A320-200 carrying 162 people lost contact en route from Indonesia's second-largest city Surabaya to Singapore. An aerial search crew on Tuesday spotted apparent debris in the Java Sea.

Reports said Indonesian navy has recovered more than 40 bodies from the sea, believed to be passengers aboard the flight, with the count rising as the search operations continue.

A search plane has also spotted a "shadow" on the seabed in the shape of an aircraft, believed to be that of the missing plane.