The victims are all from the same family and have been named in multiple media reports as Mervyn and Maree Schwarz, and Maree's son Graham Tighe. They had been living at their property near Collinsville, northwest of Mackay, for less than 12 months.

Queensland Police Mackay District Superintendent Tom Armitt said the deceased family had been invited to a gate bordering their property by a long-term nearby resident to discuss an ongoing dispute.

"There was an invitation for them to go there," he said.

Supt Armitt said a rifle was brought to the meeting, but could not confirm if the deceased family also brought a weapon along.

A fourth victim who was shot in the abdomen and then airlifted to Mackay Base Hospital, remains in a serious condition.

"He underwent surgery but he was able to converse with us last night to provide us with a version of what he saw," Supt Armitt said.

A 59-year-old man who is known to police is in custody and charges are expected to be laid today. The man is a long-term resident of the area.

The alleged gunman is one of three people being held by police.

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First responding officers who arrived on scene have been praised for their extreme bravery, and Supt Armitt said they were in "grave danger" prior to the alleged shooter being arrested.

Crime scene officer remain on scene.

A number of people were working in the area at the time and officers have called on anyone with information, including on vehicle movements in the area, to contact Queensland Police.