Dramatic footage has emerged of a NSW Police senior constable drawing his gun on a Canberra driver he pulled over for a random breath test.
The police dash cam video shows the highway patrol officer running towards the driver's side window with his firearm drawn and aiming it at the man's head at Harman, south of Canberra and just inside NSW.
His actions drew strong criticism from a magistrate when the footage was tendered in the ACT Magistrates Court on Friday as the motorist, 32, successfully fought a drink-driving charge linked to the incident.
NSW Police were reviewing the circumstances of the prosecution and the court's decision, a spokeswoman said in a statement.
The court was told the incident took place when police were carrying out roadside breath tests on Canberra Avenue in Queanbeyan on January 22, 2015.
The highway patrol officer said he noticed the motorist's car slow down as it approached the breath test station shortly after 11pm.
The driver then swerved and turned down Stephens Road, the officer said.
Police followed the driver for a short time before the man stopped in Woods Lane, which is in the ACT.
The footage shows the police officer getting out and tapping his gun twice on the driver's side window.
He then pulls the car door open and points the gun at the driver's face.
The driver can be seen raising his arms before he steps out of the car and the police officer directs him to lie face down on the road.
Once the driver is on the ground, the police officer holsters his gun and knees the man in the back before he handcuffs him, hitting him again on the back.
The senior constable told ACT police officers who arrived soon after that he had breath-tested the driver and the man had returned a positive blood-alcohol reading.
The driver was taken to Woden police station and later charged with level-three drink-driving.
Lawyers for the driver, from Ben Aulich and Associates, argued the arrest was improper given the police officer's behaviour, which they said showed excessive force.
They also said the officer had failed to disclose the exact nature of the arrest.
The driver's barrister, Jack Pappas, said the police officer had not entered any information about the use of force in his online report of the incident, which was required under police guidelines.
In handing down her decision on Friday, Special Magistrate Margaret Hunter said she was appalled the police officer had drawn his gun in the circumstances and it was clearly unnecessary to have levelled it at the man's face.
The court heard he had given evidence that he did not believe his use of force had been excessive, it was reasonable to draw his gun and he had not known he had to enter the use-of-force information in his report.
He said he had drawn the gun because the area was dark and he felt threatened as he did not know how many people were in the car.
But Ms Hunter said the video showed the area was well-lit and there had clearly been one person in the car.
She said the officer could have sat in his vehicle and waited for the ACT police officers to arrive or called for back-up.
Ms Hunter said that, while the senior constable claimed he had told police who arrived at the scene what had happened, it was clear from the evidence of two ACT police officers that he had not mentioned he had held a gun to the man's head or kneed him in the back.
She found the drink-driving offence was not proved after it emerged the breathalyser the police officer used had not been an approved device under ACT law and Canberra police had not carried out their own breath test at the scene.
Ms Hunter said that meant she was not required to make any formal finding as to whether the man's arrest had been improper. She awarded the defendant costs.