Australia and Malaysia have offered support to Indonesia in the search for AirAsia flight QZ8501 which disappeared around 12 hours ago.
Passengers aboard a ferry that caught fire rung a Greek television station begging for help, according to reports.
Nikos Papatheodosiou telephoned a station claiming that passengers "are burning and sinking" before hanging up.
Rescue crews are struggling to approach a burning ferry carrying almost 500 people off the coast of Greece due to strong winds and rough seas.
The Norman Atlantic was close to the island of Corfu when it sent a distress signal after a blaze broke out.
A Greek government minister said the rescue mission was "one of the most complicated operations that we have ever done".
Miltiadis Varvitsiotis said there were 478 passengers and crew aboard, more than the 466 originally reported.
A British national is on board the missing AirAsia flight QZ8501 and next of kin have been informed, the Foreign and Commonwealth Office said.
The AirAsia plane that has lost contact with air traffic control had conducted approximately 13,600 flights and 23,000 flight hours, Airbus has said in a statement.
The plane is an Airbus 320-200 delivered to AirAsia in 2008, the company said
Currently 6000 A320 aircraft are in service with over 300 operators, a statement added.
The manufacturer said it would co-operate with authorities investigating the disappearance and added that the thoughts of its management and staff were with all those affected by the plane's disappearance
Flight QZ8501 was between the Indonesian port of Tanjung Pandan and the town of Pontianak on Borneo island when it went missing, authorities believe.
Tanjung Pandan is the main town on Belitung island, roughly half way between Indonesia's Surabaya Airport and Singapore, the flight's departure and planned arrival points.
There was bad weather over the island at the time of the disappearance. Shortly before it disappeared, the flight's crew asked to fly higher due to bad weather.
Tony Fernandes, the group chief executive of AirAsia, has said he is on way to Surabaya in Indonesia following the disappearance of flight QZ8501.