The Ministry for Primary Industries has confirmed two more farms have tested positive for the cattle disease Mycoplasma bovis, bringing the total number of infected properties to 20.
One of the farms is in the Waimate district in South Canterbury, where the disease was first found in July last year on a Van Leeuwen Dairy Group property, while the other is in Southland.
A Ministry for Primary Industries spokesperson said 11 of the infected properties were in South Canterbury, two were in Mid Canterbury, six in Southland and one in Hawke's Bay.
Mycoplasma bovis can cause lameness, mastitis and abortions in cows, and is spread through nose to nose contact.
South Island cattle breeders had to withdraw their entries from this week's New Zealand Dairy Event in Feilding last week because of fears it could spread the disease.