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.
"These devices are highly effective and can even work in areas across some distance, where there is no cell coverage."
He said satellite GPS devices can be installed covertly on items such as quad bikes and other machinery so they can be tracked if they get stolen.
Satellite devices also do not require cell coverage to track.
Gary Deakin, of Deakin Trucks, said his trucks had been burgled several times over the years. Most recently he had four batteries stolen about a month ago.
"It was taken out of the trucks parked on the yards in Clive."
At about $150 to $200 each, it wasn't cheap to replace them.
Deakin thought the batteries might be sold as scrap metal, because they couldn't be placed in ordinary cars.
He said he'd also had several fuel caps damaged or taken off his trucks.
Deakin said he'd put in a range of security measures to try to limit the impacts of the thefts.