Thieves are targeting fuel and heavy-duty vehicle batteries in Hawke's Bay.
Police on Thursday issued a warning to owners and operators at orchards, commercial businesses and rural properties after a spate of thefts, which are being investigated.
Acting Detective Sergeant Steve Leonard said many of the vehicles were "seriously damaged" by the offenders trying to gain access to the batteries and fuel.
He urged owners to be aware and take precautions to protect their property and equipment, including locking farm equipment and commercial vehicles and storing them out of site.
Security options for farmers to consider included installing CCTV or wireless alert systems which can activate an alarm in your house to alert you that someone is in your shed by alarm or light sensors, he said.