A man who police said fired a rifle at his children, ex-partner, and members of the public is dead after being shot by officers south of Maryborough on Sunday morning.

Key points: Police received reports of a rifle being discharged at a vehicle and at several people

Police received reports of a rifle being discharged at a vehicle and at several people A 40-year-old man was found at a house but was critically injured by members of the Special Response Team

A 40-year-old man was found at a house but was critically injured by members of the Special Response Team The Police Union says the officers were left with no option but to act in self-defence

Police Superintendent Craig Hawkins said police received reports of a man armed with a rifle travelling around the town of Tiaro in a car on Saturday night.

"Early indications are that he had a dispute with his ex-partner that has led to the weapon being discharged or fired at her vehicle, at her and her children," he said.

"One of the weapons he was using was an extremely high-powered rifle."

Superintendent Hawkins said the man also shot at a neighbour and fired at someone when he tried to get fuel.

The police helicopter and specialist officers were brought in to search for the man through the night.

The 40-year-old was found at a house on the outskirts of the town at about 7:00am.

"Unfortunately this man was in an elevated position as police arrived," Superintendent Hawkins said.

"He fired upon police and also charged police with a weapon.

A bullet hole in the neighbour's ute. ( ABC News )

"Police responded by returning fire towards the man."

The man was critically inured by members of the Special Emergency Response Team.

He died at the scene.

'I find it hard to sleep'

A neighbour of the gunman said he helped the man's ex-partner escape.

Later in the night, the gunman allegedly approached the neighbour armed with a rifle.

"[He] came over to my place, put some bullet holes through my car, stuck the gun in my face," the neighbour said.

"When he was not on what he was on, whatever that was, very nice fella, but then turned into a dead set idiot, carrying on like a Rambo-type person.

"I still haven't got over it. It's a terrible thing to happen. I find it hard to sleep."

Queensland Police Union secretary Mick Barnes said officers acted "bravely and appropriately".

"Police were left with no other option than to act in self-defence and to also protect the public," he said in a statement.

"We are extremely lucky that police and members of the public were not killed or seriously injured by the offender."