Mycoplasma bovis has not been confirmed in Northland, MPI says, despite some reports that it has.
Last week, two farms in the region were put under a Notice of Direction by MPI while testing for the cattle disease took place.
"This is a precautionary measure while under testing," an MPI spokesperson said yesterday.
Federated Farmers Northland dairy chairman Ashley Cullen said he was particularly worried about the cattle disease after seeing a map of the number of traces in Northland.
Forward traces were where a farm has had cattle moved from an potentially infected or suspicious farm.
"We haven't got that much information yet. We've got two areas that we think might be contaminated, Tangiteroria and somewhere in the Hokianga."
The stock on the farms potentially affected at the moment were beef cattle, not dairy cows, he said.
"But that could change by the end of the day."
Cullen said he was particularly concerned as a farmer himself who has recently bought stock.
"We bought some heifers in for this season so we're a bit worried. And that was the first time in years."
A Notice of Direction meant that cattle could not be moved off the farm without a permit, but was not as strict as a Restricted Place Notice (RPN), which restricted movement of all stock and risk goods.
Federated Farmers Northland president John Blackwell said that Northland farmers want an independent inquiry into the disease.
Mycoplasma bovis was confirmed in Waikato just over a week ago. The only other confirmed cases in the North Island were in Hawke's Bay and a farm near Pahiatua.
The disease was first detected in New Zealand in July last year at a farm in South Canterbury.