Bay of Plenty police are searching for "several stolen diggers" that have been taken in the last couple of months.
In a written statement, Senior Sergeant Graham Perks said police believed diggers were being stolen because they were considered "high ticket items".
"While police do patrol in these areas regularly, we encourage owners to keep vehicles safe, by taking some very basic precautionary measures."
He said there were ways to do this "without it costing too much".