Families of those killed in an AirAsia plane crash in Indonesia demanded Monday the airline apologise for negligence after a probe showed faulty equipment contributed to the accident, a year on from the tragedy that left 162 dead.

Flight QZ8501 plunged into the Java Sea in stormy weather on December 28 last year during what was supposed to be a routine flight from the Indonesian city of Surabaya to Singapore.

Relatives of some of the passengers, AirAsia officials and the head of Indonesia's search and rescue agency gathered Monday in Surabaya, the country's second-biggest city, for a private ceremony to remember those killed in the crash.

It came just weeks after Indonesian investigators' final report showed a chronically faulty component in a rudder control system, poor maintenance and the pilots' inadequate response were major factors in the crash.

Ahead of the ceremony, an association set up by victims' relatives to push for reform of Indonesia's beleaguered aviation sector demanded an apology from AirAsia.

"We the families demand AirAsia apologise openly to victims' families for the negligence that has resulted in fatalities," said a statement from the group.

The statement added that the families were "surprised and shocked" the report showed the chain of events that triggered the accident was set off by "negligence" with regard to the faulty component.

Sunu Widyatmoko, chief executive of AirAsia's Indonesian affiliate, refused to comment on the accident report following the ceremony.

The crash of the Airbus A320-200 was the first major setback for the Malaysia-based budget carrier after a spectacular 13-year run of success.

The families also demanded the government stop AirAsia from flying the Surabaya to Singapore route, and called on Indonesian authorities to improve aviation safety following a series of air disasters in the country in the past year.

The Indonesian probe found the component, which had cracked soldering, suffered problems 23 times in the 12 months before the crash, and cited issues with maintenance.

During the ill-fated flight, the component malfunctioned several times, prompting the pilots to reset a computer system in a bid to fix it. But the plane's autopilot was disabled in the process, leading the crew to lose control.

The crash was one of several aviation accidents in the sprawling archipelago over the past 12 months.

In August, a turbo-prop plane operated by Indonesian domestic carrier Trigana crashed in the remote eastern region of Papua during a short flight in bad weather, killing all 54 people on board.

And in June an Indonesian military plane went down into a residential neighbourhood in the city of Medan, exploding in a fireball and killing 142 people.