A Northlander who smashed a ute into three power poles to hurt his partner has been sentenced to more than six years in jail.

The actions of Peter John Orchard left his partner with bruises all over her body and resulted in her spending three days in hospital while their children, who were in the back seat, were unhurt but traumatised.

The 38-year-old was sentenced to six years and nine months in jail when he appeared for sentencing in the High Court at Whangarei this morning.

He pleaded guilty to single charges of attempted murder, causing grievous bodily harm with intent to cause grievous bodily harm, dangerous driving, breaching a protection order, and two of common assault.

The Crown withdrew the charge of attempted murder at sentencing.

Justice Mathew Downs said Orchard was driving his partner and three children to Kerikeri on January 6 when he became upset about a text message she received.

The exact nature of the text message was not known but it concerned allegations about him.

Justice Downs said Orchard became very upset and said he had nothing to lose and made other remarks.

Orchard then deliberately drove off the road into several road signs and then at three lamp posts.

Before hitting the first of the three, he undid his partner's seat belt and ensured the line of lamp posts were on her side of the vehicle.

Orchard ran the first two lamp posts down, the third caused the car to flip and rest on its passengers' side.

She was not unconscious but had to be cut free by firefighters from Kerikeri.

Justice Downs said Orchard's partner had a protection order against him at the time of his offending.

He used his car as a weapon and the offending involved extreme violence, the judge said.

He said Orchard's partner was vulnerable as her head was likely to have suffered the bulk of the injuries.

Orchard was disqualified from driving for six months.

The disqualification would start on his release from jail.