After a lengthy trial, an Indonesian court on Monday found Marwoto Komar guilty of criminal negligence over the 2007 crash at Yogjakarta airport.

But despite the unprecedented conviction, several Australians, including former foreign minister Alexander Downer, said they thought the sentence was too light.

Komar was captain of the Garuda Indonesia plane when it slammed on to the runway at Yogjakarta airport, careered into a field and burst into flames on March 7, 2007.

In a majority verdict, the Sleman District Court found Komar could have taken steps to avert the disaster.

''In the landing stages the defendant was not careful, and should have coordinated better with his co-pilot,'' one of the five judges said.

Komar, wearing his pilot's uniform despite being stripped of his licence, immediately declared he could not accept the verdict and intended to launch an appeal.

The court did not order Komar into immediate detention, meaning he will not go to jail until a higher court orders it.

Scores of people, including relatives of those who perished in the crash, packed into the tiny, hot courtroom to hear the verdict. Judges spoke for more than three hours before announcing their decision.

Caroline Mellish, sister of Australian Financial Review journalist Morgan Mellish who died in the crash, said she felt two years' jail was not enough.

''I don't feel that justice has been served,'' she said outside the court.

The other Australians killed were diplomat Liz O'Neill, AusAID official Allison Sudradjat, and Australian Federal Police officers Bruce Steele and Mark Scott.

All were travelling to the central Java city in connection with a visit there by Mr Downer, who criticised the court's decision.

''It seems a very light sentence frankly,'' Mr Downer said.

''I understand from the evidence that was presented that there was nothing mechanically wrong with the aircraft and that the pilot just landed the plane at far too high a speed, way over the limit of the landing of an aircraft.''