Vic chair murder not frenzied: court

A man fatally bludgeoned his partner with a chair, but it was not a premeditated murder or a frenzied attack, a Melbourne court has heard.

Hampton Park man Steve Ray Cook, 24, is facing a plea hearing at the Victorian Supreme Court after being found guilty of the 2014 murder of Sharnee Ngatai, 23.

"The picking up of the chair, and striking her with the chair, was something completely unexpected," defence barrister Michael Cahill said on Monday.

Police were called to the couple's home in January last year where they found Ms Ngatai with serious injuries.

She died a short time later in hospital.

Mr Cahill conceded Cook's attack on Ms Ngatai was brutal, but said it was not a "sustained beating".

He said it was a "snap reaction" to emotional stressors, exacerbated by intoxication.

"It was a single, fatal wound," Mr Cahill told the court.

"Your Honour could not find it was a frenzied attack."

A group, including Cook, had been drinking at the couple's Hampton Park home before the killing.

The court heard Cook was woken up, triggering the attack on Ms Ngatai.

He did not remember the incident and had shown remorse, Mr Cahill said.

The plea hearing continues.