Indonesia’s Transport Ministry has threatened to revoke AirAsia’s licence for flying on an unauthorised schedule when its plane crashed with 162 people on board.

The ministry said on Saturday that the Malaysia-based budget airline has now been suspended from flying the route from the city of Surabaya to Singapore, the same route Flight 8501 was flying when the accident happened on Sunday.

"It violated the route permit given, the schedule given, that's the problem," Djoko Murjatmodjo, director-general of air transport, told AFP news agency.

He said AirAsia's permit for the route would be suspended until investigations were completed, while other airlines in the country would also be examined.

"We will carry out an audit or an evaluation on all airlines in Indonesia over whether there are any violations related to route, time and schedule," Djoko said.

It remains unclear how the airline had been able to fly without the necessary authorisation.

Ministry investigating

A statement from JA Barata, spokesperson for Indonesia's Transport Ministry, said AirAsia Indonesia had not been permitted to fly the Surabaya-Singapore route on Sundays, and had not asked to change its schedule.

"The minister is investigating not only the airline, but also the air traffic control tower, Surabaya airport and the people within the ministry responsible for giving out time slots for airplanes to fly," she said.

"Also, all other routes and airlines are now being investigated for similar violations. If found guilty, the minister threatens to ground them all."

Al Jazeera's Step Vaessen, reporting from the capital Jakarta, said: "Even before we have come to know the reason for the fatal accident, the minister of transportation has made some very bold statements.

"He has suspended AirAsia's Surabaya-Singapore route because he says the airline had no licence to fly on that particular day: it has no licence for Sundays and can only fly during the week.

"But it has been confirmed that AirAsia has been flying on that route every Sunday, so the minister is talking about a big investigation because many questions are being asked."

Sunu Widyatmoko, AirAsia Indonesia's chief, said the company would not comment until the results of the investigation were known, adding that the airline would "fully cooperate with the government in that evaluation process".

Aircraft parts found

The news of the schedule violations came amid reports that major parts of the Airbus A320-200 were found in the Java Sea off the island of Borneo late on Friday night.

The news raised hopes that the remaining bodies and the "black box" recorders, crucial to determining the cause of the crash, would soon be located.

Search teams have found 30 bodies of those killed when the plane, delivered in 2008, went down early on Sunday during a storm.

Search leaders were sending divers to the spot where plane parts had been found to try to recover the remaining bodies.

"With the discovery of an oil spill and two big parts of the aircraft, I can assure you these are the parts of the AirAsia plane we have been looking for," Bambang Soelistyo, the head of the search and rescue agency, said.

"The main focus today is to find and evacuate victims."