Second police shooting in Qld three days

A man remains in an intensive care unit in hospital after being the second man shot by police in three days in Brisbane.

The man was in a 'very serious condition' when he was rushed to hospital on Thursday afternoon.

Police say his condition hasn't changed and an internal investigation is underway into the shooting.

The man was armed with a knife when confronted by an officer who first used a Taser before firing several shots at the alleged robber, police say.

The shooting, which is being investigated by Ethical Standards Command, occurred about 2pm on Thursday at Oxley, about 10km southwest of Brisbane's CBD.

Detective Superintendent Tony Fleming says the man, who was known to police, was allegedly involved in a series of incidents after first stealing a vehicle in the neighbouring suburb of Darra.

The stolen vehicle then struck another vehicle on Oxley Station Rd, Oxley.

The carjacker, in possession of a knife, then got out and attempted to steal another car.

After stealing the second car, he struck another man aged in his 20s with the vehicle. The man had come to the aid of the distressed female driver.

"The male then attempted to steal another car but was unable to leave the car park," Det Supt Fleming said.

An officer, riding solo, arrived on the scene and confronted the assailant, who had a knife, in a nearby park.

"It's my understanding the officer attempted to negotiate with the man and he discharged a Taser... that was not successful.

"He was then threatened with a knife, where he feared for his safety, and discharged a number of rounds."

"The man was struck a couple of times in the torso."

On Monday night, police shot and killed a man who had doused himself with fuel and set himself alight at Sunnybank Hills.

Ethical Standards Command is investigating both shootings.