The Australian Transport Safety Bureau (ATSB) is investigating the possibility that an electronic device caused pilots to lose control of a plane leading to the injury of dozens of passengers.

Qantas flight QF72 from Singapore called in a mayday and had to make an emergency landing after the pilots lost control at 37,000ft.

The plane made a series of violent manoeuvres that left 12 people seriously injured and 30 in need of medical attention.

"A preliminary review of the data indicates that, after the aircraft climbed about 200ft from its cruising level of 37,000ft, the aircraft then pitched nose-down and descended about 650ft in about 20 seconds before returning to the cruising level," said the ATSB.

"This was closely followed by a further nose-down pitch where the aircraft descended about 400ft in about 16 seconds before returning once again to the cruising level."

Investigators are examining all possibilities and have held talks with Airbus, which manufactured the plane, to see whether the cause can be analysed.

An investigator told the Melbourne Herald Sun that the inquiry will look at whether electronic items may have caused the problem.

"Certainly in our discussions with passengers that is exactly the sort of question we will be asking: 'Were you using a computer?,'" said an ATSB representative.

Computers and mobile phones have long been citied by some as dangerous to use on planes, and they cannot legally be operated until the aircraft has reached 3,000ft.

"It is well known in the electrical engineering community that the operation of electronics systems, including air navigation systems, may be adversely affected by electromagnetic interference," said Chris Zombolas, technical director at EMC Technologies, which tests electromagnetic interference.

"Could a laptop computer or mobile phone have caused Qantas QF72 to plunge? The answer is 'yes'," he said.

However, press reports now suggest that the fault lay not with onboard laptops, but with the aircraft's control software itself. Investigations are continuing.