A Hamilton teenager who subjected his partner to a series of violent and potentially lethal assaults - including throttling his partner with a power cord so hard she passed out - has been jailed for three years and nine months.

Satriani Mihinui, 19, was sentenced in the Hamilton District Court on Monday, for what Judge Noel Cocurullo described as "fairly brutal violence".

It was violence that was inflicted during arguments with his partner in December and January in Hamilton and Waitara.

Mihinui faced a raft of charges including injuring with intent to injure, assault with a weapon, male assaults female, and assaulting police.

The worst of these altercations happened on an unspecified date between Boxing Day and January 1.

Mihinui had recently been released from Waikato Hospital, where he had been receiving treatment for an infected toe.

He and his partner began arguing. Mihinui grabbed a long, orange extension cable and wrapped it around the woman's neck, pulling it tight. She attempted to scratch and hit him as he was doing this.

Eventually Mihinui relaxed his grip and took the cord off. He began apologising and kissing and hugging the woman.

As the police summary of facts notes, the victim then looked into his eyes and asked: "Why did you stop?"

He wrapped the cord around her neck again and began strangling her.

This time she lost consciousness and began twitching. Mihinui relented when he saw what was happening.

Another assault on January 13 involved him punching his victim to the head multiple times, including after she fell onto her knees before him. He also kicked her in the head with his shin. One of his blows caused her nose to bleed profusely. She also suffered a black eye.

Rather than help her, Mihinui locked her in an outside shed to avoid anyone else seeing what he had done to her. He left her locked in the shed overnight.

Mihinui's violent reign over his household came to an end on January 22 following yet another argument - to which, this time, there was a witness.

In that incident Mihinui had pushed his partner down a hallway and into a shed and had also thrown asthma inhalers at her.

The other person saw some of this, and told Mihinui they were calling the police. Enraged, he pursued the other person and threw a metal chair and a bottle of Heineken beer. He missed both times.

The police arrived. Mihinui locked himself inside the house. While the police were attempting to speak with him through a window, Mihinui unexpectedly smashed the window, showering the two officers outside with broken glass. They both suffered minor lacerations.

Mihinui armed himself with a chair and smashed another window, again sending glass over the police. They pepper sprayed him, and he was arrested.

In explanation during a police interview, he said attacked his victim because he wanted to hurt her.

As part of sentencing Mihinui, Judge Cocurullo approved a request for his victim to be granted a protection order.

"You are a most serious and violent offender," the judge told him. "Your partner is in clear and present danger from you. You will seriously hurt her or kill her ... You have complete and utter disrespect for her. I see your strangulation activity as some of the worst violence there is."

From a start point of 30 months imprisonment on the injuring with intent to injure charge, the judge uplifted that period by 27 months to account for all his other charges.

He added four months to reflect Mihinui's previous offending, and another four for the offences he committed while on court bail. Five months were subtracted, to reflect the defendant's young age and expressions of remorse.

The judge then applied a 25 per cent discount, to account for Mihinui's guilty pleas, ending with a final sentence of 45 months in prison.

- Stuff/Mike Mather