Indonesia's transport minister proposed a number of changes to improve aviation safety standards at a parliamentary hearing on Tuesday, just over three weeks after an AirAsia passenger jet crashed killing all 162 people on board.

Ignasius Jonan also told the hearing that, according to radar data, the plane had ascended faster than normal in its final minutes, after which it stalled.

He said that a number of new rules regarding permits and safety, including health checks for flight crews and air traffic controllers, have been implemented since the crash.

"It is a habit among airlines that they sometimes sell tickets before they have obtained a route permit," Jonan said. "Now route permits must be obtained 4 months before the flight and airlines will not be allowed to sell tickets before that."

The transport ministry has suspended AirAsia's Surabaya-Singapore licence for flying on a Sunday, for which it did not have permission. However, the ministry has said this had no bearing on the crash.

Jonan added applications for route permits and air transport licences would be moved online next month. The ministry had also recommended that wages for operations personnel like maintenance and safety inspection officials be raised, he said.

President Joko Widodo has called for an urgent overhaul of the Indonesian aviation sector, which is among the fastest-growing in the region but has seen airlines with patchy safety records mushroom to cater to demand from a growing middle class.

Analysts say infrastructure has failed to keep up with the boom in air travel in Southeast Asia's biggest economy, leading to overcrowded airports.

Investigators have yet to determine why the Airbus A320-200 crashed into the Java Sea about 40 minutes into its flight, but bad weather is believed to have played a factor.

"The plane, during the last minutes, went up faster than normal speed ... after then, it stalled. That is according to the data from the radar," Jonan said.

A source familiar with the investigation's initial findings told Reuters last month that radar data appeared to show Flight QZ8501 made an "unbelievably" steep climb before it crashed, possibly pushing it beyond the Airbus' limits.

Investigators are analysing data from the aircraft's two "black box" flight recorders to determine exactly why it crashed. They said on Monday they had found no evidence so far that terrorism played a part in the disaster.