Tereza Anne Loone, 28, gave evidence for the defence in a disputed facts hearing in the Launceston Supreme Court.

Her fiancé, Cameron James Brasher, 26, pleaded guilty last month to numerous charges, including three counts of aggravated assault upon three police officers.

Brasher has been in custody since he fired a double-barrelled sawn-off shotgun four times at police on February 25 at Poatina.

No officer was physically harmed and none fired their weapons.

The defence believes that if Justice Robert Pearce finds a number of issues in Brasher's favour, these will be mitigating factors in sentencing.

Loone accompanied Brasher when he committed his crimes.

She was fined in the Launceston Magistrates Court last month for several summary charges relating to her involvement with the Poatina shooting.

During evidence-in-chief today, Loone said that she woke up in a car with Brasher on the morning of February 25 and she heard sirens.

She said that Brasher got into the driver's seat and as he drove through the car park they were in, she saw a police officer with his gun drawn, about 20 metres away from their car.

"He had his gun pointed at the car," Loone said.

"I believe he fired because I heard a loud bang.

"I screamed and I ducked down."

She denied seeing any physical evidence accompanying the "bang" but she thought one of her three dogs, which were riding inside the car, had been shot.

Loone said she checked the yelping dog but it was not harmed.

Justice Pearce adjourned the matter to October 27.