The ACT Policing investigation into a shooting incident at Canberra Airport last Sunday continues, and police are seeking additional witnesses.

While many witness statements have been gathered, investigators believe there are people who were in or around the Canberra Airport check-in area in the lead-up to, and during the shooting who have not yet spoken to police.

In particular, police are asking anyone who had family members or friends who used the airport early Sunday afternoon, and who witnessed any suspicious behaviour to contact police if they have not already done so.

A similar call is being put out to any travelers from interstate who used the airport around that time, who have since returned home, to speak to police if they witnessed anything relevant to the shooting.

Anyone with relevant information is urged to contact Crime Stoppers on 1800 333 000 (or via www.crimestoppers.com.au) and quote reference 7187298. Please note, anyone calling from outside of the ACT, should call ACT Policing on 02 5127 0051.

The alleged gunman, Ali Rachid Ammoun, 63, is in custody and has been charged with a series of firearm offences for the shooting on 14 August.

No one was harmed when Ammoun allegedly shot his handgun at a window of the airport from inside the lobby.

Ammoun’s case returns to court on 5 September. The NSW man is yet to enter a plea.

He has been charged with discharging a firearm at a building, unlawful possession of a firearm and discharging a firearm near a person causing alarm.

Police allege Ammoun fired a number of shots from a handgun into windows about 1.25pm on Sunday before being apprehended by federal police stationed at the airport.

Ammoun had not passed into the terminal and so had not been screened.

No one was injured during the incident but the airport was evacuated and remained closed for about three hours.

Canberra Airport boss Stephen Byron said there were no plans to introduce further security.

With AAP