A man has been shot dead by police during a siege in the Elwomple area near Tailem Bend, south-east of Adelaide.

Police were called to a house occupied by Alex Kuskoff on Elwomple Road just before 7:00pm on Wednesday.

Kuskoff had been making threats to kill a number of people over the phone, which led to police being called out to his property.

When the patrol arrived, he refused to cooperate with police and ran back into the house, police said.

STAR Group officers, negotiators and the police helicopter were also called out to the scene.

Police said over the course of several hours Kuskoff shot at police.

Just before 12:00am, he allegedly shot at STAR Group officers, who returned fire, fatally wounding him.

A neighbour Sam said he was shocked and saddened by the incident.

"He was a really nice, quietly spoken, sort of gentlemanly man," he said.

Assistant Commissioner Bronwyn Killmier said numerous shots were fired over the five hours.

STAR Group officers attempted CPR, however, the 50-year-old died at the scene.

Ms Killmier said officers involved in the incident would be offered support.

"The incident highlights the dangerous work police do. It's a dangerous set of circumstances," she said.

"We always try to resolve these type of incidents safely for everyone, and it's not really an outcome we would have hoped for.

"We attend thousands of mental health incidents every year, and our aim is to resolve them peacefully at all times."

Investigators from Major Crime Investigation Branch and Physical Evidence Section attended the scene and will investigate the circumstances surrounding the man's death.

Police said a report would be prepared for the coroner.