A woman who saw her son bleed to death after he was stabbed with a broken beer bottle has told a Sydney court she still calls his phone to hear his voice.

Sateki Siale, 26, was in August found guilty of murdering Kelly Ventigadoo, 45, outside his Lakemba flat in October 2015.

He admitted smashing a beer bottle on a brick fence then using it to fatally strike his neighbour twice in the neck.

Mr Ventigadoo’s parents witnessed the frenzied attack by Siale, who had complained the trio was talking too loudly.

Fighting back tears at Siale’s sentencing hearing at the NSW Supreme Court on Friday, Cynthia Ventigadoo said she would always picture that “terrible night” in her mind.

“The man appeared out of nowhere and attacked him,” Ms Ventigadoo said. “There was blood everywhere, even on myself.

“We never expected our son to die this way right in front of us and so quickly.”

She cried every night for her son, she said.

“We miss him so much that I would ring his phone just so I could hear his voice.”

Siale apologised to his victim’s family and friends in court.

“I know he’s left a big dent in your hearts,” Siale said.

“I don’t expect forgiveness but I just want to say I’m sorry.

“I don’t know what else I can do.”

The trial heard Siale had been drinking for six hours before the attack.

He admitted on Friday that alcohol had got him into trouble on numerous occasions, saying: “I’m never going to touch alcohol again.”

Prosecutor Jose Crespo said Siale knew he became “aggressive and violent” when he drank alcohol.

He said Siale had an “intention to kill” when he inflicted the second blow on Mr Ventigadoo.

“He must have been able to see the damage that was inflicted by the first blow,” Mr Crespo said.

Siale is due to be sentenced on September 29.

-AAP