UPDATED 4.56PM: On just his second day on trial, former Whangarei police Detective Sergeant, Michael Blowers has pleaded guilty to drug charges.

Michael Blowers appeared in the High Court today accused of stealing seized methamphetamine and then supplying it to a drug dealer.

Blowers pleaded guilty to both charges this morning, however an additional charge of selling cannabis has since been dropped.

The Crown claimed the offending occurred between the 1st of June 2011 and the 31st of June 2012.

The Crown says Blowers was capable of stealing drugs by transferring them to a storeroom he had unlimited access to.

Police became suspicious when the purity of a 2 oz bag of methamphetamine seized from the Burgundy Rose Hotel was re-tested and found to have dropped significantly. It was then discovered a portion of the bag had been replaced with table salt.

Defence Lawyer Arthur Fairley says new Crown evidence which was brought to his attention on Tuesday, showed Blowers as the only person who could have tampered with the drugs.

Mr Fairley says after assessing the evidence on Wednesday he then advised Blowers it would be unanswerable.

He says Blowers is aware he has let himself, his family and the community down.

Blowers fall from grace comes after 20 years in the police force, 15 of which were in the criminal branch.

He was the Head of the Northland Organised Crime Unit, which primarily dealt with drug offences, giving him privileged access to seized material.

Blowers has been remanded on bail and awaits sentencing on December 3.