Officials in Indonesia say they are confident substantial wreckage of the missing AirAsia plane has now been located after sonar equipment detected four huge objects on the ocean floor.

It comes as reports suggest AirAsia could be banned from offering flights in Indonesia, after it emerged that flight QZ8501 was not authorised to fly on the day it plunged into the Java Sea.

The company also faces allegations that the pilot did not ask for a weather report from meteorologists before take-off, amid concerns that the Airbus A320 was downed in stormy conditions.

Indonesia's transport ministry has suspended all AirAsia flights between Surabaya and Singapore – the route where the plane went missing in the early hours of 28 December.

The budget airline's other schedules are also under investigation, as it was not permitted to make this journey on Sundays.

Earlier, ships searching for the wreckage pinpointed "four big objects" on the seabed, with underwater remote operating vehicles attempting to capture images of the debris.

No survivors have been found from Flight QZ8501, which had 162 people on board. Crucial black boxes revealing what happened in the plane's final few minutes are yet to be found.

Some of the objects found during the search | Image: Facebook/Ng Eng Hen - Defence Minister

On Friday, 21 bodies were recovered from the Java Sea - including two passengers who were still strapped in their seats - taking the number of confirmed victims to 30.

Efforts to recover passengers have been hampered by strong winds and high waves, scattering debris further afield. An emergency slide and exit door were initially discovered, along with cameras and children's food.

"Many of the passengers are believed to be still trapped inside the plane's fuselage and could be discovered soon," one search official said. "God willing, we will complete this operation next week."

The pilot, who had 6,100 flying hours on the A320, had asked to ascend to 38,000ft before contact was lost with air traffic control.

Radar data appears to show that the plane made an "unbelievably" steep climb before it crashed, possibly beyond the capabilities of the aircraft.

On Friday, AirAsia's chief executive Tony Fernandes attended the funeral of one of the flight attendants who lost their lives on flight QZ8501.

Hundreds of people attended the burial of Khairunisa Haidar Fauzi, which took place in her hometown of Palembang in south Sumatra.

Originally published at 13.34