An ACT Policing spokesman confirmed on Tuesday a 59-year-old woman from NSW had been killed in the crash at the intersection of Bowen Drive and Brisbane Avenue.

After some incorrect alleged witness accounts were published on social media, United Firefighters Union secretary Greg McConville moved to clarify events.

He said all sources the union had communicated with confirmed the fire engine had been travelling with lights and siren activated.

The crew involved in the collision immediately began performing a rescue on the woman, cutting her free from the wreckage, and rendering medical assistance, Mr McConville said.

He said any suggestions first responders hadn't done their job properly could add to post-traumatic stress experienced by emergency service workers.

However, he didn't want to distract from the fact "someone has lost their life in very tragic circumstances" and extended condolences to the woman's family.

Emergency Services Agency commissioner Georgeina Whelan also extended her sympathies to the woman's family and friends.

She said staff would receive support from management and peers.

Mr McConville said firefighters dedicated their career to saving lives and it was very difficult for the crew, who were responding to a fire alarm, to then have to provide assistance after being involved in the collision.

The ACT Policing spokesman said the crash was subject to a coronial investigation by the crash investigation and reconstruction team.

Anyone with information was asked to contact Crime Stoppers on 1800 333 000 or via the Crime Stoppers ACT website.

The woman's death marks the fifth fatality on ACT roads this year.