trial for six Comanchero bikies accused of murdering a man at Sydney Airport has heard their leader was provoked by the victim.

Opening the defence case for the Comancheros, Philip Dunn, the lawyer for their leader Mick Hawi, said Hawi's behaviour during the violent airport brawl was "a case of reactions - not actions".

He reminded the Supreme Court jury sitting at Parramatta that his client has pleaded not guilty.

Anthony Zervas, the 29-year-old brother of a Hells Angels bikie, was killed in the March 2009 fight.

The crown case is that Mr Zervas was chased before being bashed with metal bollards, stabbed and kicked.

The jurors have previously heard that the brawl started after a chance meeting between members of the rival clubs on a domestic flight from Melbourne.

But Mr Dunn said prosecutors have "started on the wrong track" because there is evidence that Mr Zervas ran at Hawi to try to attack him first.

Referring to witness accounts he said "one eyewitness varies to another".

The trial, before Justice Robert Allan Hulme, is expected to last six months.

Airport passengers and staff will be among the witnesses.

Comanchero bikies Hawi, Farres Abounader, Ishmail Eken, Zoran Kisacanin, Christian Menzies and Usama Potrus, have pleaded not guilty to murdering Mr Zervas.

Hells Angel David Padovan has pleaded not guilty to a charge of riot.

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