Wellington City Council has sacked nine staff members over the past five years for failing random drug tests.
Council spokesperson Richard MacLean says a 10th person was fired after being tested on the grounds of reasonable cause for concern.
He says the council's policy applies to staff who may deal with machinery or with members of the public.
Mr MacLean says staff who test positive are given counselling and monitored and if further tests are positive the council reserves the right to terminate contracts.
He says the dismissals show the system works and the council is reassured not too many of its 1500 staff are taking risks with drugs.