A man has died after being tasered and shot by police at Wannanup near Mandurah, south of Perth in the early hours of Sunday morning.

Police said they had been called to an area near Rod Court in Wannanup, not far from The Pines restaurant and function centre, after reports of a man acting suspiciously.

While patrolling the area around 12:20am, they came across a man with a knife.

Acting Deputy Commissioner Paul Steel said the man dropped the knife, but then picked up another, larger one.

"He then subsequently armed himself with a larger knife and began advancing towards the officers," Commissioner Steel said.

He said the man "ignored repeated requests to drop the knife" and began advancing towards the officers, who discharged tasers at him.

"Both officers discharged their tasers, unfortunately, their tasers were ineffective," he said.

When the man continued to advance, one of the officers fired at him using a police firearm, Commissioner Steel said.

Officers 'acted appropriately'

Police tried to resuscitate the man and he was taken to Peel Health Campus by ambulance, where he later died.

Homicide squad detectives and officers from the Internal Affairs unit are investigating the incident.

Comissioner Steel said one of the officers was an experienced male sergeant, the other a female constable.

He would not disclose which of them fired on the man.

Alan Wenlock says the fatal police shooting of a man on his street was "an incident waiting to happen". ( ABC News: Briana Shepherd )

Only one shot was fired by the officer who was "directly at threat", he said.

Commissioner Steel said he had no concerns about the way the officers acted in the situation.

"The officers appear to have acted in accordance with their training," he said.

He said police were still working to identify the man and notify his family.

Residents shocked

Wannanup resident Alan Wenlock said the area had been a "haven for drug dealers" at night.

He said it was a good community throughout the day, but it was different at night and what happened was "an incident waiting to happen".

Mr Wenlock said he had been asking police to take action on the issue for some time.

Aurora Collins was at home with her six children when she heard gunshots.

Aurora Collins lives near where the incident occurred and heard the gunshots. ( ABC News: Briana Shepherd )

"We heard the gunshots and we heard the cop cars come up and then we saw the ambulance there and they brought the stretcher out and put the person on the stretcher and put them in the car and took off lights and sirens, both the ambulance and the cop car behind," Ms Collins said.

"Then I saw this morning that the guy had passed away."

She said it had been quite upsetting for her family.

"It's pretty scary really especially with the amount of kids and how many people actually go fishing down there.

Wannanup is adjacent to the Dawesville Channel and near the upmarket Port Bouvard marina and luxury canal development, about 90 kilometres south of Perth.