A policeman ran over and killed a 16-year-old pedestrian seconds after receiving a text message from a young woman he had met at a rugby club function, says a coroner's report.

The officer also did not have the headlights of his patrol car on high beam, although he was driving at night on an unlit, rural road.

Coroner Garry Evans today released his findings into the death of Northland teenager Rawiri Wilson, who was struck by the patrol car driven by Constable Jamie Anderson on State Highway 1 near Ohaeawai.

Mr Wilson's death might have been avoided if the officer had his lights on high beam, Mr Evans found.

The officer's actions were inconsistent with those expected of a "reasonable and prudent driver".

He also said there was an "aura" of suspicion that Mr Anderson might have been distracted by the text.

The teenager's grandmother said last night that the family still struggled to deal with the pain caused by the July 2009 death.

Mr Anderson initially refused to let the coroner see his cellphone records, and when asked whether he had opened the last message, replied, "I don't know. I just can't remember."

A search warrant had to be issued to discover the timing of the text message - an estimated 23 seconds before impact - but it could not determine whether Mr Anderson had opened the message.

During the inquest, Mr Anderson said he was confident he had not looked at it before the crash.

The constable was described by colleagues as a "fairly frequent texter", and at the scene, the officer who was with him asked, "You weren't texting, were you?"

Legislation banning the use of mobile phones while driving had not yet come into force.

The coroner said it was unwise for Mr Anderson to have been driving without high beams, and suggested legislation to recommend their use on dark roads.

"Constable Anderson's act of driving with headlights dipped in the dark conditions prevailing on the road at the time in question was inconsistent with that reasonably to be expected of a reasonable and prudent driver."

He would have had at least twice as much time to react if he had been using his high beam.

An Independent Police Conduct Authority report is still to come. But Mr Anderson will not face criminal charges, and a Northland police spokeswoman said he remained in the force.

Mr Anderson and Mr Wilson both began their evenings at parties on opposite ends of the Northland town.

Mr Anderson was picked up at 4.30pm by police colleagues from a function at the Ohaeawai Rugby Club for a patrol.

The patrol spent at least an hour during the evening outside the rugby club - where Mr Anderson made "fleeting" contact with two young women at the party.

He kept in touch with one of them during the night by text messaging.

Mr Anderson left the rugby club at 11.25pm to drive a colleague home - and he was seen using his cellphone as he pulled out of the driveway.

Mr Wilson was at his uncle's 60th birthday party, 1.3km east of town on State Highway 1, with his 16-year-old cousin and 14-year-old brother.

They had smoked "a couple of cones" of cannabis before the party, and drank about six stubbies of beer each at the function before walking into town and back again on the dark rural road.

Mr Wilson's brother walked in front, on the road's gravel margin. His cousin was in the middle, walking on the white lines. Mr Wilson followed behind, about 1.3m from the left edge.

The trio were within 50m of their uncle's driveway when Mr Anderson came down a rise and took his patrol car along an easy right turn - while receiving a text message from the young woman.

His headlights were dipped, and all he saw was the bottom part of a leg.

Mr Wilson's brother turned around to see Mr Wilson and his cousin in the air, after a sound that he told his family was like an explosion. The cousin survived with a hip fracture, but Mr Wilson died at the scene.

Mr Wilson's grandmother, Ada Morton, said the brother still had trouble dealing with the incident almost two years on.

"Right now he's a very angry young man, and we're looking into getting some counselling - for me as well as him," Ms Morton said.

"He's so angry it's not funny ... I keep telling the police he needs help because he never acted like that before."

She did not want to open old wounds again, she said, but many questions about the incident remained unanswered. "Every now and then I think about it and get angry. But I think, what's the point? You just get on with life the best you can."