A man shot dead by police on Brisbane's outskirts during a domestic violence incident was wearing camouflage tactical gear and carrying a long-arm rifle, according to the police union.

The 48-year-old man allegedly confronted police who arrived at a house on Cavill Place in Narangba about 12.30am after reports of a domestic disturbance.

It was reported the man had been making threats, and Queensland Police Union's general president Shane Prior said the situation escalated rapidly.

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"When police arrived, they saw a man known to police come to the front door … dressed in camouflage, armed with what appeared to be a rifle," he told media.

"That man directly threatened police with that rifle. They chose to use lethal force, both using their service-issued firearm, each firing a number of rounds."

Prior added the man was wearing a tactical vest and had "some sort of army background".

Neighbours said they heard shouting and police urging the man to drop his weapon multiple times, before hearing gunshots.

"They asked him about five times to drop the gun," one neighbour said.

"We heard four gunshots and a pause, and then another gunshot," another said.

Officers provided first aid and CPR, and paramedics arrived soon after, but the man died at the scene.

There was a woman, an 18-year-old and a teenager in the home at the time, all of whom were related to the man.

They were taken to hospital for emotional distress.

Prior said initial investigations suggested there may have been mental health issues at play.

"Tragically, suicide by cop is a very real thing that needs to be investigated here," he said.

Prior added the union was fully supporting the police officers involved, both of whom were impacted by the shooting.

"Both officers are very shaken up by today's incidents, one more than the other," he said.

"This is a very traumatic event."

Acting Superintendent Kerry Johnson confirmed there were other people in the house at the time of the shooting, and that the man who died was subject to some form of order, though he refused to confirm if it was a specific domestic violence order.

"When police arrived, he was originally inside. [They] were making their inquiries at the front door, this other interaction with a family member, and that's when he's confronted police," Johnson said.

"It's happened very quickly, and unfortunately these are the things that happen in policing, it can escalate and de-escalate."

Nobody else was injured and police say there is no ongoing risk to the community.

As the shooting is classed as a death in custody, it is now a coronial matter. Ethical standards command is also investigating the shooting.

Johnson said he could not make a full judgment on the validity of the police officers' actions this early in the investigation, but he believes at this early stage, there is no cause for concern.

"It's up to the officers at the time to determine what they're going to do… unfortunately, the 48-year-old with his confrontation and behaviour, unfortunately [forced] them to escalate and the action was taken," he said.

"It's alarming to do what we have done, but there's nothing at this stage to cause concern about the police actions."

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