Indonesia's transport ministry said there are 155 people on board missing Air Asia Indonesia flight QZ 8501 - 149 Indonesians and six foreigners including one Singaporean.
The other foreigners are one British national, one Malaysian and three Koreans. One of the Korean nationals is an infant, said the ministry.
Indonesia's Metro TV reported that there were 138 adults, 16 children and one infant. It said the plane had two pilots, four cabin crew and one technical staff.
QZ 8501 was travelling from Surabaya, Indonesia to Singapore on Sunday morning when it lost contact with Indonesian air traffic control.
"AirAsia Indonesia regrets to confirm that flight QZ8501 from Surabaya to Singapore has lost contact with air traffic control at 07:24 hrs this morning,'' said an airline statement.
"Search and rescue operations are in progress and AirAsia is cooperating fully and assisting the rescue service,'' said the airline.
AirAsia has established an Emergency Call Centre for family or friends of those who may have been on board the flight. The number is +622 129850801.