Four to face court over Cheng murder

Four young men accused of planning the murder of Sydney police accountant Curtis Cheng are due to face court.

The men - aged 18, 20, 22 and 23 - were on Wednesday charged with conspiring an act in preparation of a terrorist attack, almost seven months since Mr Cheng was shot dead by 15-year-old Farhad Jabar in Parramatta.

Police will allege the chief suspects worked in concert with Jabar, who was shot dead by police after the attack.

The 18-year-old man is accused of supplying the gun that was used in the murder and has been charged with directing the activities of a criminal group.

The 20-year-old meanwhile organised the travel of Jabar's sister to Syria on the day before the attack, police say.

All the men have already been charged with other offences since Mr Cheng's death, including knowingly making funds available to a terrorist organisation and aiding the commission of a terrorist act.

They are expected to appear in Goulburn Local Court via video link on Thursday.