Wellington police say a tourist, who left a hard drive containing hundreds of objectionable images of young children in a rental car, had been travelling alone in the country for the past few weeks.
The hard drive was discovered on Monday afternoon, but the 45-year-old British passport holder had left New Zealand by the time police got involved.
Detective Senior Sergeant John van den Heuvel said they have briefly looked at the images and doubt they were taken during his stay in this country.
"He entered New Zealand on the 12th of October and after that we're not sure of his exact movements."
Police are tracking the man's whereabouts overseas.