A parasite that can be lethal to cattle has now spread to 473 North Island farms.
Eleven new herds a week are being infected with the parasite, theileria ikeda, which makes cattle anaemic and in severe cases is killing livestock.
Dairy NZ team leader of animal husbandry and welfare Nita Harding says while most infected herds have only one or two sick animals, there's anecdotal evidence some cattle are dying.
And she says it's not just dairy farmers who need to be on the look out for sick stock and there are a number of cases in beef farms and even in some drystock farms.
Ms Harding says there have been a few cases in Wairoa Mahia Peninsula area, as well as in the areas where it was seen earlier such as the Hauraki Plains, around Hamilton, towards Raglan and in Northland where the first cases were seen.
The Ministry for Primary Industries says it's possible the disease got into the country in cattle imported from Australia.