A judge says a man who killed his younger brother in a drunken car-surfing accident on Mt Maunganui beach would be behind bars if it was "someone else's kid".

Instead, Luke McGregor was sentenced yesterday to five months' home detention after the accident that claimed the life of his brother Jordan.

The court heard that 25-year-old McGregor was driving a four-wheel-drive on the beach with Jordan, 23, riding on the bonnet when he hit an 8m-long log.

"The vehicle was thrown into the air, and your brother flew off the bonnet," Judge Louis Bidois told McGregor during sentencing in Tauranga District Court.

"Sadly, unfortunately, the vehicle landed on top of him. What started out as a harmless bit of fun has ended up in tragedy."

Judge Bidois said no one had expressed concern about Luke's driving, and his speed was not excessive, but he should never have let anyone ride on the bonnet.

The court had to send a strong message against drink-driving and dangerous driving, the judge said, and the typical sentence would be 18 months to two years in jail.

But he reduced that because of mitigating factors including McGregor's guilty plea, remorse and the fact that it was his own brother who was killed.

"That relationship and that closeness means it can open the door to home detention. If it had been anyone else, there would be calls for blood. The reality is, when there's dangerous driving, drink-driving and death, unless there's an extreme, there's a need of imprisonment. If this was someone else's kid, he would be going to jail, full stop."

In February, McGregor, his two brothers and friends had spent the day fishing before going to a beach.

McGregor managed to squeeze his vehicle between two posts on a pedestrian beach access at Mt Maunganui.

He parked on hard sand and the group drank alcohol into the early morning.

About 1am, McGregor took the steering wheel and the group clambered in - except for two young men. One grabbed on to the back of the vehicle and Jordan lay on the bonnet, clutching the windscreen wipers.

Luke McGregor was over the breath-alcohol limit, at 446 micrograms. The limit is 400.

He turned on the headlamps and took the four-wheel-drive down the beach at 70km/h. He did not see the log until it was too late.

It has been estimated the vehicle flew 10m before hitting Jordan.

McGregor stood in court motionless and expressionless as he was sentenced for dangerous driving causing death.

Defence lawyer Max Simpkins said McGregor had "become subdued and withdrawn" since the accident.

Judge Bidois said: "He's going to be like that for a very long time because of what happened ... That will live with everyone for the rest of their lives.

"It was a waste of a life. Had this been one of your friends or a mate of some sort, it would have been a double tragedy, and 18 months to two years [in jail]."

He also sentenced McGregor to 140 hours of community work and disqualified him from driving for 18 months for the drink-driving.