He was discharged on charge of supplying cannabis.
The veteran officer had 20 years' experience on the job, with particular expertise in battling the drug trade.
He was the officer in charge of the Northland Organised Crime Unit which carried out raids against drug manufacturers and suppliers.
He resigned two weeks before his arrest in April last year.
At his sentencing today Justice Geoffrey Venning said Blowers explained his offending by saying he had taken the drugs to protect his family from perceived gang threats.
He said Blowers' explanation did him no credit.
"You were a senior police officer. You know and would have been well aware of the resources available to the police. You and your family could have been protected.
"The irresistible inference is that the real reason you took the drugs was because of your relationship with the informant and in order to make money.
"If you and your family had genuinely been threatened by gangs there were steps the police could and would have taken to protect you and, importantly, your family and you know that."
However, he said Blowers was "remorseful" and had acknowledged his actions had humiliated his family by placing them in an emotional and financially strained situation.
"You have lost the home you had built up with your wife and you have suffered the very public humiliation of a significant personal fall from grace."