A police prosecutor convicted of using methamphetamine and cannabis still faces an internal employment investigation.

Brent William Thomson, 49, was a prosecutor in Auckland based at the central police station.

In Waitakere District Court today, he was convicted and fined $450 after earlier pleading guilty to three charges relating to possessing and using methamphetamine and cannabis.

An application to discharge Thomson without conviction was rejected by Judge Hemi Taumanu.


Inspector Mike Johnson, operations manager for the Police Prosecution Service, told APNZ Thomson remained suspended as an employment investigation continued.

"Police take these matters extremely seriously and where appropriate will put any matters of a criminal nature before the court," Mr Johnson said.

"Police staff are held to account under the law just as any member of the public is."

Outside court, Thomson told Newstalk ZB his future in the legal profession was up to the Law Society and he wouldn't practice at the moment as he would be unable to do the best for his clients.

He said his sentence was fair and generous.

"Methamphetamine is a dangerous drug, it's a powerful drug, and recovering from it is better than living with it."

Thomson's lawyer Mark Manhire said drugs could take a hold of anyone, regardless of intelligence, education or upbringing.

Police Association president Greg O'Connor wasn't available today but has previously said the public should have faith in the police service.

Court appearances by police employees were not a sign of a corrupt service but a healthy one, as it would be much worse if such cases were not brought before the courts.

Mr O'Connor said it was important to remember Thomson wasn't a police officer, but a lawyer employed by the police.

Thomson's sentencing follows a number of other cases where police staff have faced drug-related charges.

In May last year, Auckland prosecutor Tim Sarah was jailed for four years after admitting five charges, including supplying methamphetamine and dishonestly accessing the police intelligence computer system to get confidential information.

Sarah also sold methamphetamine during his lunch break and passed secret information from police files to his drug dealer.

West Auckland policeman Peter Pakau will this year face trial on charges relating to methamphetamine and accessing the police computer system.