Only following a police shooting do officers undergo drug and alcohol testing. (File photo).

Random drug testing is yet to be introduced by the police, two years after the then deputy police commissioner said there were plans to bring it in.

Information released under the Official Information Act shows it is only mandatory for police to be drug and alcohol tested after a police shooting.

They do not undertake random testing, and said just 17 staff members had undergone voluntary tests from 2012 until 2017, and all produced negative results.

Previously, officers were also drug tested after critical incidents that caused serious harm, but since March testing is only mandatory after shootings.

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This is contradictory to statements made in 2015 by then deputy police commissioner Mike Clement, that all staff involved in critical incidents, which had resulted in death or the discharge of a firearm or serious injury, may undergo mandatory testing.

He also said the police planned to bring in random drug testing for 500 staff in safety-sensitive roles.

Labour police spokesman Stuart Nash was surprised police still had not introduced random drug testing.

"It sort of baffles me why they haven't taken this opportunity to be at the forefront of this."

Apart from making sure the community was safe, Nash said random drug testing looked good for police as they were the moral authority against taking drugs.

Nash said he felt it was unlikely there would be police taking drugs, but random testing helped put confidence in them.

"I have no doubt police don't use drugs, but let's make sure we have the evidence to back that up."

Independent Police Conduct Authority general manager Warren Young said they had recommended police do drug and alcohol testing after critical incidents.

"We do not consider it adequate that testing be confined to shootings. It should occur after other critical incidents as well."

A police spokeswoman said that as soon as reasonably practical after a shooting, the officers who fired shots are required to be tested for drugs and alcohol.

"If a positive result is obtained the employee will be given an opportunity to respond to the result and to seek retesting of the sample, within five working days of being notified of the test result, if they wish."

In all cases, police would take steps to address an employee's rehabilitation and welfare needs.

"Disciplinary procedures may apply, which may result in the employee being issued with a warning or dismissed from their employment."

A staged approach was being taken in the implementation of drug and alcohol testing, and she said the first step was to introduce testing following a police shooting.

Police were working alongside the New Zealand Police Association and the New Zealand Police Managers Guild to introduce wider testing to the organisation, with work near completion.

Police Minister Paula Bennett said it would be inappropriate to comment on operational matters.