Sydney/IBNS: Western Australian police shot and killed a "radicalised" 16-year-old boy with a knife who had wounded a person in Perth, media reports said Sunday.

The teenager "rushed" at police after wounding someone from the public. He was then fatally shot by an officer, Premier Roger Cook told a news conference.

"There are indications he had been radicalised online. But I want to reassure the community that at this stage it appears he acted solely and alone," he said.

Police received a call late on Saturday from a male warning that he was going to commit "acts of violence".

However, he did not reveal his name or location, the state's police commissioner, Col Blanch, told reporters.

Within minutes another emergency call alerted police that a "male with a knife was running around the car park" in Willetton, a southern suburb of Perth, he said.

Police body camera images showed the teenager refused officers' demands to put down his knife, said reports.

It was then officers fired two Tasers at him but "both of them did not have the full desired effect," he said.

"The male continued to advance on the third officer with a firearm who fired a single shot and fatally wounded the male."