The security footage showing the lead-up to the shooting as the policeman aims his gun.

Authorities are investigating an incident on Monday where a policeman shot dead a pet dog in a street in Perth, Western Australia.

Security video, shown on Australia's Nine News, shows a male police officer drawing his gun when the Staffordshire Bull Terrier approaches him.

The video shows the dog, called Biggy, wagging its tail and then sitting down just before the officer fires a single shot and kills the dog.

Interviewed for the TV news report, the dog's owner Pat Wharram said he was disgusted by the actions of the police officer.

He is threatening to sue the force.

"He was gunned down for nothing. He sat for him. He was wagging his tail. I'm just cut up by this," Wharram said.



"DISTURBING"

NINE NEWS Biggy and another one of Pat Wharram's dogs escaped from his home.

Police minister Liza Harvey told Radio 6PR that the incident was being investigated, describing the footage as "disturbing".

"What we'll be looking at was whether it was appropriate for that firearm to be discharged and used in this manner for that incident," she said.

"I'll leave that up to the authorities to investigate."

Nine News reported that Biggy and another one of Wharram's dogs escaped from his Banksia Grove home and walked roughly 10km to Kinross.

Police received reports the dogs had acted aggressively towards young families in a park. They were described as fighting each other and growling and baring their teeth - although no-one was attacked.

One of the dogs was caught by a ranger but Biggy ended up approaching the armed police officer.

Wharram says he is considering legal action against the police because he feels he was lied to.

"I'm just disgusted that the police told me lies. I was told he attacked an officer," he said.

Nine News reported that Western Australia police had released a statement saying that the officer had discharged his firearm because he feared he was about to be attacked.