A Teviot Valley farmer is concerned about Transpower New Zealand's vehicle movements on the area's dairy and beef properties, which he says could spread the cattle disease Mycoplasma bovis.
However, Transpower has assured farmers it has biosecurity management procedures and policies in place to mitigate any risks.
The company's service contractors need to drive over properties to inspect high-voltage structures and they were out and about in the valley during the past couple of weeks.
Retired farmer Peter Macdonald, of Millers Flat, said it was ''irresponsible'' of Transpower to inspect the network at this time of year, when stock were being wintered from other areas, including Southland, and concentrated in paddocks.
''We've got a notice from Transpower about contractors inspecting pylons around Roxburgh but about this time of year there are dairy herds being grazed and they could spread M. bovis from property to property.''