A gunman who fired five shots inside Canberra Airport says he committed the crime to send a message to the Australian government.

Ali Rachid Ammoun, 63, pleaded guilty both to last year's shooting and to possessing a revolver without authorisation.

He faced the ACT Magistrates Court for sentencing after seven months in custody, and to hear how the incident had affected witnesses.

At the time of the shooting in August last year, Ammoun was on parole for attempting to murder his ex-wife in 2007. He had stabbed her 27 times and also tied up and bashed his mother-in-law.

Ammoun was sentenced in Western Australia in 2009 for those offences.

After he was released on parole last year, he moved to Sydney.

On the day of the shooting, he caught a taxi directly to Canberra Airport, three hours' drive away.

Once inside the airport, he fired his handgun five times at the windows.

The gunfire sparked a panicked evacuation. Police officers moved in to disarm Ammoun as terrified witnesses fled, some fearing a terrorist attack was underway.

'This is not a victim-less crime'

The bullets smashed three windows but did not harm anyone directly.

However, 15 witnesses attended Ammoun's hearing to tell the court how the incident had affected them.

One of the victims broke her leg while she was fleeing the gunfire.

In an impact statement, she described being at the airport with her parents and two young children.

"Everyone started screaming and running everywhere," she said.

The woman's father told the court of his terror, saying he did not know "if there was one person or 10 people with guns".

"My family will never be the same: this is not a victim-less crime," he said.

The man's wife broke down while discussing the events, saying she assumed it was a terrorist attack.

She said she could not talk about that day without crying.

Another witness who spoke in court included a woman who said she was trapped with her baby and her blind sister.

She recalled her panic, saying "months down the line, we all struggle travelling in airports".

"You bore no consideration to the people in the airport that day," she told Ammoun.

A school teacher told the court the trauma had left her unable to work for five weeks.

"I'm not the same person I was before this incident."

Gunman's first public comments

Ammoun also addressed the court, making his first public comments about the shooting.

He said he had spent three days deciding whether to travel to the capital before eventually catching the taxi from Sydney.

He added he had never intended to harm anyone; rather, the shooting was a "message for the Australian government".

"It's nothing to do with Canberra or the people in Canberra," he said.

"I spent 16 years in a Western Australian prison for a crime I didn't commit. No one listened to me."

Ammoun will be sentenced next week.