A masked man who held up a petrol station in the suburb of Hornby in Christchurch and took $800, remained at large on Monday.
The man pointed a pistol at the attendant and demanded cash and cigarettes before making off on foot just before 6am on Sunday.
Police said the incident has taken a toll on the attendant who was traumatised by it.
A police dog picked up the offender's scent for a short time, but eventually lost it.