Police have charged five people from a family, including a set of 18-year-old triplets, after seven police were injured while responding to a domestic violence incident in Sydney's south-west.

The Bankstown family allegedly launched the attack on police, leaving one with a black eye, another with a bite wound and others concussed and bruised, police said.

Police had to call for back up and use capsicum spray to subdue their alleged attackers.

A 46-year-old man, a 21-year-old man, two 18-year-old men and an 18-year-old woman were arrested at the scene and taken to Bankstown police station.

They were all charged with affray, assault police, hinder police and resist arrest. One of the 18-year-old men was also charged with assault occasioning actual bodily harm.

All five have been refused bail to appear at Parramatta Bail Court on Thursday.

Police responded to reports of domestic violence at a family's house in Ogmore Court, Bankstown, about 12.35am on Wednesday.

When officers were leaving the house via the driveway, one of the family members allegedly punched a probationary constable in the face, leaving him with a black eye.

About six other family members joined in the attack as officers tried to stop them, police said.

A man who lived on the street said the police were called to the home because of a loud family dispute.

"It was only a verbal fight but nothing physical. We don't know who called the police but the violence started when they arrived," he said.

"I think the problem was the police went on to the property and the brothers were angry about that. They were shouting at the police. Yelling. They wanted them to go.

"Police started using pepper spray and it was going everywhere. It really got out of hand."

The five family members were taken to Bankstown Police Station, where they were questioned before being charged.

Three officers were treated at Bankstown Hospital, but have been released.