The activity was largely driven by high demand for four-wheel drive parts, both in New Zealand and internationally, Mr Parnell said.
"Police will be taking a hard line where any offending is identified. The bottom line is that car thefts would not be occurring on the scale we're seeing if it wasn't for receivers who are creating a ready market."
Police had spoken to those in charge of the business but they were yet to be formally interviewed. No charges have been laid at this stage, Mr Parnell said.
Investigators had visited several other parts and scrap-metal dealers in the area but no other stolen vehicles were found, he said.
"Our message to dealers is that they must be vigilant about their customers and their record keeping."