Whanganui murder: Labour MP Kiri Allan's estranged brother sentenced to 14 years in prison

The man who murdered a Whanganui woman by hitting her repeatedly in the face has been sentenced to a minimum of 14 years' prison.

Eric Ara Mete, the estranged brother of Labour MP Kiri Allan, was on a five-day methamphetamine binge at the time, using 1-3g a day.

Mete was sentenced by Justice Francis Cooke in the High Court in Whanganui today, with a full public gallery watching and relatives of the victim, Lorna-Anne Marie Thompson, fronting up to him.

Thompson's daughter said her mother was kind and loving, and Mete couldn't handle her strong-minded words and actions. Thompson's brother said Mete had brought shame on the whānau.

Her mother said Mete had used Thompson for what he could get out of her.

"Why did you make my mokos motherless for the rest of their lives?"

Mete and Thompson had been in an on-and-off relationship for six to eight months when the murder happened. They were living together in a flat over a shop on the corner of Victoria Ave and Ingestre St.

They were at home on April 6 when they got into an argument in the living room, Justice Cooke said. Mete became enraged and struck Thompson numerous times in the face, aiming for her eyes and nose.

Multiple bones were broken, and her face was "concaved" to the point where people later found it unrecognisable. When Mete realised he had killed her, he tried to clean blood off in the bathroom and then sat down and used cannabis and methamphetamine.

He left the flat, and when he returned he tied Thompson's hands together, dragged her into another room and tried to clean up. He came and went for a few days, then admitted to a relative in Turangi he had killed her.

The relative told police and Mete handed himself over to them. Thompson's body was found on April 10.

His chaotic and violent early life began at Ratana, Justice Cooke said. His parents separated when he was 10 and he started using inhalants then, and cannabis at 13.

His violent behaviour became a problem and he was expelled from school at 12, and again at 14 when he went to Auckland to live with his father and was around people using harder drugs.

He lived in Australia for a while, under the steadying influence of a sister, but resumed substance abuse on his return to New Zealand. He is 51 and has six children, but has little or no relationship with them.

Mete had little loyalty and put substance abuse ahead of relationships, Justice Cooke said.

"You have been living a life without any true sense of your place in the world."

The murder was particularly brutal and callous, and happened in Thompson's house where she had a right to feel safe. On the other hand, Mete had been genuinely remorseful, took responsibility, had good family support and was motivated to change.

He will serve a minimum sentence of 14 years, and his counsel Debbie Goodlet said he accepted he would be spending the rest of his life either in prison or on parole.

Even though Mete is the brother of Allan, the pair didn't grow up together.

The Labour MP said the murder brought shame to the whānau, and her thoughts and aroha are with Thompson's family.