The shootings took place while the family had gathered to celebrate their mum.

The mother watched on as her stepson allegedly shot her son at close range in the chest, according to The Daily Telegraph.

Emergency services were called to a property at Bingleburra near Dungog on Sunday about midday, following reports a man had been shot, police said in a statement.

Witnesses told police the argument between the stepbrothers, aged 35 and 28, began about midday, turning into a brawl. The younger stepbrother then went into the house at the rural property and got a .22 calibre rifle, according to The Daily Telegraph. The man then allegedly shot his older stepbrother in the chest at close range.

He then ran from the property, according to police.

He was found some time later by passers by, who found him critically injured on the road near the property with a gunshot wound to his head. Police described the man’s gunshot wound as self-inflicted.

As emergency vehicles arrived at the scene, both men were treated for their injuries before they were flown to John Hunter Hospital.

A spokesperson from the hospital told news.com.au the younger man was in a critical condition, the older man in a serious condition.

Officers from Port Stephens-Hunter Police District attended the property and established a crime scene, which will be examined by specialist forensic officers.

Inquiries into circumstance surrounding the incident continue.

If you or someone you know needs help, contact Lifeline on 13 11 14.