Cattle disease Mycoplasma bovis continues to spread through New Zealand with a farm in Cambridge the latest to test positive.

The Ministry for Primary Industries biosecurity business unit, Biosecurity New Zealand, confirmed the news today.

The Waikato region dairy farm was identified through the tracing of cattle movements from infected properties and has been put through an exhaustive testing process to achieve a reliable result.

The farm is under strict controls preventing the movement of animals and other risk goods on and off the property.

Biosecurity New Zealand's Director, Response, Geoff Gwyn says it was very disappointing to find the disease in another of New Zealand's key dairying regions.

"It was, however, not a huge surprise, given the sheer number of farms we are uncovering that have received cows and calves from affected farms," Gwyn said.

"It's a reality of New Zealand's farming system that large numbers of animals are sold and moved across big distances. This response is serving to underline just how much movement takes place and it is this, coupled with poor record keeping through NAIT that is making our job very challenging."

The new Cambridge positive takes the number of infected properties across the country to 39.

Prime Minister Jacinda Ardern said MPI was working hard on containment plans.

"This Government [is] having to pick up the pieces of neglect and underinvestment, it's shameful."

The disease posed no threat to humans but it needed to be brought under control.

Ardern said it was brazen for the issue to be made political given it arose some time ago.