The Ministry for Primary Industries has raided three properties as part of its investigation into the cattle disease, mycoplasma bovis
Its manager of compliance investigations, Gary Orr, said the searches relate to 'potential breaches of legislation'.
The breach could be of the Biosecurity Act in regards to importing genetic material.
Genetic material includes semen, embryos or drugs.
To date there has been no answers from MPI on how the disease got into the country, but the ministry has been investigating it for over six months and a report is expected this week.
A recent study confirmed that the disease can be spread through frozen imported semen, which follows speculation last year that this could have been how mycoplasma bovis got into New Zealand.
MPI said yesterday it conducted simultaneous warranted searches at three locations as part of an investigation associated with the mycoplasma bovis response.
The searches were in both the North and South islands.
Mr Orr said MPI can't comment while investigations are underway.
"We recognise there is strong interest in the rural sector concerning how mycoplasma bovis may have entered New Zealand.
"We will ensure the outcome of these investigations is communicated to farmers as soon as we are able to provide that information."
Federated Farmers Dairy Chair Chris Lewis said it's an unusual move from the ministry.
"It's a surprising development, especially after the announcement this week saying they are going to cull 22,000 cattle ... there's a lot of speculation around how it came into the country...
Mr Lewis couldn't confirm if the searches were at farms, laboratories, or other businesses.
"From my understanding, it could be farms and other places ... but that's just pure speculation.
"I've been to the MPI presentations and they didn't rule out imported semen or embryos, or pharmaceutical products... so obviously it's one of those three that they're doing more work on."
The search warrants shouldn't change the ministry's decision to cull over 22,000 cattle, he said.
Mr Lewis said the warranted searches give farmers hope that MPI is confident it has the disease contained, and knows how it got into the country.
MPI said its compliance staff have the right to apply to the courts for a search warrant, then it's over to the courts to grant that application.
It said that obviously in this case, the applications were granted.
The disease was found in July on a dairy farm in South Canterbury.
It has spread to about 30 properties from Southland to Hawke's Bay.
Earlier this week MPI announced that more than 22,000 cattle on that tested positive for mycoplasma bovis would be sent to the slaughterhouse by May.