A senior policeman who admitted driving while nearly one and a half times over the legal alcohol limit was let off after a judge decided it was more important he stay working.

Sergeant Jason Lamont, 39, was pulled over last August with a reading of 113mg of alcohol per 100ml of blood.

The Auckland officer was charged with excess blood alcohol and pleaded guilty in the North Shore District Court in April.

But Judge Phil Gittos discharged Mr Lamont without conviction, saying his role and experience outweighed the importance of the conviction.

"The judge basically took the view that it effectively wouldn't be in the public interest for an experienced and well-regarded senior police officer to be out of a job," defence lawyer Steve Bonnar told the Weekend Herald.

"That the public's better served by having him remain in the police."

Mr Bonnar applied for the exemption under Section 106 of the Sentencing Act, which says any person charged with an offence, who is found or pleads guilty, may be discharged without conviction unless "by any enactment applicable to the offence the court is required to impose a minimum sentence".

However Judge Gittos did disqualify Mr Lamont from driving for six months and ordered him to pay court costs, as the act also allows the court to make "any order that would be required to make on conviction".

Mr Bonnar said his client had misjudged the amount of alcohol he drank before driving.

"The facts were a little bit strange," he said. "It was a situation where he'd only had a couple of beers, but he'd had a family gathering earlier in the afternoon. He believed he was perfectly fine and he was only just over the limit."

The rules on whether police officers are automatically dismissed after a drink-driving conviction are unclear.

A police national headquarters official said a convicted officer "would be the subject of an ongoing investigation".

Auckland City Police spokeswoman Noreen Hegarty said Mr Lamont was still "a serving member of the Auckland city police" and was the subject of a code of conduct inquiry.

Mr Lamont could not be reached for comment yesterday, but when the Weekend Herald phoned the main switchboard, the call was transferred to the Mt Wellington community policing team.

Mr Bonnar said it was up to judges to determine whether the consequence of conviction outweighed the offence.

In Mr Lamont's case, Judge Gittos had found it did not.

The case follows the recent conviction of a Northland officer for drink-driving.

Senior Constable Ross Kneebone, 53, pleaded guilty to drink-driving after blowing 733mcg of alcohol per litre of breath at a checkpoint last September.

He applied for a discharge - hoping to remain working as an unsworn officer - but Judge Duncan Harvey said he should not be treated differently to others. Police also opposed the application.

Meanwhile Senior Constable Craig Fraser, formerly of the Auckland serious crash unit, is back in court next month on a drink-driving charge.

The 47-year-old has been charged in relation to an incident in the carpark of a North Shore fast food restaurant last year.

It is understood an off-duty Mr Fraser backed into a stationary car and drove off.

He was later breath-tested by colleagues.

Yesterday he told the Weekend Herald he would not return to policing because he had broken "the code of honour".

* Taranaki, 2008 - Constable Hamish Hardy, 29, resigned after crashing a patrol car while drunk
* Wellington, 2008 - Superintendent Graham Thomas, a former police national prosecutions manager, refused a breath test. Police clear him but the Independent Police Conduct Authority said his behaviour was misconduct.
* Auckland, 2008 - Constable Matt Hooper avoided a blood alcohol test at the station by emerging from the toilet with a head injury and going to hospital. [The law says blood taken in hospital for alcohol testing can't be used in court unless the person is there because of a car crash].