The Geoff Wilson Drive resident said a woman he knew as a near neighbour knocked on his door and said she "needed help" around 7pm on Friday.
She was distressed and asked to use his friend's phone to make a 000 call to police.
While they were waiting for police to arrive the neighbour heard a man inside the woman's home at Geoff Wilson Dr making threats to a person he believed to be the woman's teenage son.
"I want to fight you. I'll kill you," is what he heard.
The neighbour said when the teenage son went to enter the Geoff Wilson Dr home the woman taking refuge at his place yelled, "Don't go there. He'll kill you."
Police rushed to the scene and the neighbour heard officers instruct the man, who had been making threats, to come out of the house.
"No mate, no," was his reply, according to the neighbour.
He was unsighted to what took place next and then heard a firearm discharge twice.
"I heard two guns shots, that's it," he said.
Queensland Police Union of Employees General Secretary Mick Barnes said police officers had responded to a domestic violence incident "of a considerably violent nature" on Geoff Wilson Drive, Norman Gardens, just after 7pm on Friday.
Officers surrounded the house, before two male constables, believed to be in their 20s and with around three to four years' experience, came face to face with the New Zealand man.
The man allegedly came out of the house with a "couple of knives", threw one at one constable and then charged at both of them.
Both constables were armed with a taser and firearm. The taser was ineffective, requiring the immediate use of the firearm, said Barnes.
The man received critical injuries during the incident and was pronounced dead at the scene.
"Because of that useful force option, the aggressor, has succumbed to his injuries and that is not an outcome that anyone wants," Barnes said.
"Unfortunately they have had to use their situational force model and use deadly force options.
"These officers have had to use these use of force options to defend themselves from certainly deadly options that have brought forward by this individual," Barnes said.
The officers were both wearing body cameras which footage from will be used in the investigation.
"We are quite lucky today we are not dealing with death of one or more officers or perhaps a innocent civilian," Barnes said.
The Australian Ethical Stands Command is investigating the matter and if it was necessary for the police officers to use their weapons and deadly force.
"This is what police are trained to do, it is not something they certainly want to do," Mr Barnes said. "It is not something that is used lightly."
He said the Union was "110 per cent" behind the officers and their actions.
"It is a very difficult position to make within split seconds," he said. "Their welfare both emotional and mentality is paramount to us as a union.
"The officers were quite courageous in choosing their use of force options."
District Officer Capricornia Police District Ron Van Saane would not reveal many details regarding the incident or the victim due to the early stage of the investigation.
"As the matter is under investigation it is inappropriate for me to make further comment," he said.
He noted the work of the officers and said "it has been a traumatic event for everyone involved and we have provided support for the police offers involved and the next of kin".
He could not confirm if the man was a resident of the home.
Van Saane told media at the scene that the man was armed with at least one knife.
The police officers were wearing body cameras during the shooting. Australia's Ethical Standards Command is investigating the incident, which is subject to oversight by the Crime and Corruption Commission.
