A ''surge'' of activity in the Mycoplasma bovis programme does not represent increased spread of the disease, nor does it change confidence that eradication will be achieved, programme director Geoff Gwyn says.
The programme was increasing activity in the lead-up to autumn and winter stock movements.
That meant there would be a surge in the number of properties contacted about the movement of risk animals and a higher number of properties than usual be placed under movement restrictions.
''This is happening in a short period because of increased surveillance late last year, which has resulted in a peak in the number of high-risk properties that we have identified, and the desire to get ahead of the curve before autumn and winter stock movements get into full swing,'' Gwyn said in a statement.
About 300 farmers would be contacted as a priority over the next few weeks who have had high-risk animals move on to their property.
It was expected 250 of those would have Notice of Direction movement controls placed on them immediately and, following testing, that 10 per cent to 12 per cent might become confirmed properties.
About two-thirds of the properties were beef farms and the remainder dairy.
In an email to farmers, Beef + Lamb New Zealand chairman Andrew Morrison said some farmers had been in contact regarding the large number of properties being talked about and requesting greater clarity about how that had come about.
In particular, the large number of beef properties expected to be put under movement control was ''concerning'', especially at a time of the year where many farmers were expecting high movements, either within their own beef operation or in conjunction with dairy farmers for grazing, Morrison said.
B+LNZ would be working with DairyNZ and the Ministry for Primary Industries over the next week to provide greater detail to farmers on how the situation had arisen, the wider strategy and timing, and how farmers could best manage risks and potential disruption to their business.
Gwyn said there were about 800 other properties that would be contacted about very low-risk animal movements and it was expected less than 0.4 per cent of those properties would become confirmed properties.
To achieve eradication, it was ''vital'' the movement of high-risk animals was prevented before Moving Day on June 1 and winter grazing movements.
MPI believed there was another year of intensive surveillance, movement controls, and depopulation before the bulk of the eradication effort was completed.
MPI and its industry partners DairyNZ and B+LNZ were beginning a programme of advice to farmers on how best to manage the risk of M. bovis in winter.
This week, it would be releasing new tools for its regional teams to use to support farmers under regulatory controls that needed to make winter grazing movements and help them plan.