The police expect to start random drug and alcohol tests for officers in certain roles from next year.
Commanders say new policy is being developed in response to workplace safety legislation and several recommendations from the Independent Police Conduct Authority (IPCA).
Deputy Police Commissioner Mike Clement said it was anticipated testing would be a requirement for staff involved in critical cases resulting in death or the use of police firearms.
There would also be random tests on about 500 staff involved in "safety-sensitive" roles each year.
Police not 'immune'
Mr Clement said the police force was not exempt from the problem of drugs in the workplace.
"While we do not believe police has any particular identified issue regarding the use of drugs or alcohol by staff, we should not think of ourselves as immune from the impact of these substances as workplace hazards," he said.
The move followed the recently-enacted Health and Safety at Work Act 2015, which reinforced an existing legal duty to take all practicable steps to ensure workplace safety.
It also followed reports by the IPCA on a "number of critical incidents involving police".
The deputy commissioner said it would bring police in line with their counterparts in Australia and the UK, as well as the New Zealand Defence Force and the Department of Corrections.
Police are still developing the policy with the Police Association and Police Managers' Guild.