Stephen Boyd sentenced to a maximum 33 years in prison for killing former partner Tina Kontozis

A young man has declared domestic violence should not be tolerated after his father was jailed for a maximum 33 years for murdering his mother south of Sydney.

Shortly after his father Stephen Boyd was sentenced, 19-year-old Daniel spoke to reporters about the issue.

"I believe justice has been served," he said.

"Domestic violence must not be tolerated at any level and we must as a community do everything we can to stop it."

His father was heavily drunk when he attacked Tina Kontozis in their Bundeena home in 2016.

He stabbed her with multiple knives and bashed her with a baseball bat at the property.

Daniel heard her screaming as he ran home, and when he was eventually let inside he could see blood on his father’s hands.

He yelled, "what have you done?", before finding his mother on the floor. He was then also attacked with the bat.

Boyd fled and was arrested only after a manhunt and police chase.

He told officers, "I'm not denying, I did what I did… I just lost it."

He also tried to blame police for the murder.

Officers took out an Apprehended Violence Order against him, which meant he was not supposed to approach his family within 12 hours of drinking.

"To do this day I still believe the police should not have been called… all it did was make things worse because the police overreact," Boyd said in a letter read out to the court today.

Justice Julia Lonergan described that attempt to shift responsibility as "despicable".

She said it was a "brutal, prolonged, vicious and appalling" attack on a "defenceless woman".

Boyd barely reacted to the sentence.

A white ribbon on his chest, Daniel then walked away with the dozens of people at court to support him and his mother.