The cattle disease Mycoplasma bovis has now been confirmed on a Waimate farm that last week was "under suspicion".
This brings to eight the number of properties where the disease has definitely been detected.
Another one that was suspected last week of harbouring it is awaiting definitive test results, and yet another in the Waimate district was announced on Wednesday as in doubt and being tested.
Two of the three new farms border properties owned by Aad and Wilma van Leeuwen, where the disease was first confirmed in mid-July, the first time it had been discovered in New Zealand although it is widespread globally.
The news has resurrected questions about where the disease may have come from, and renewed calls for New Zealand to introduce an import health standard for semen.
Federated Farmers dairy group chairman Chris Lewis said dairy leaders at the recent International Dairy Federation meeting in Europe had told him the most likely means of transmission was semen.
"The semen is treated with antibiotics but there is research to show these kill lots of diseases but not Mycoplasma."
A Ministry for Primary Industries (MPI) spokeswoman said it had recently reviewed and revised its risk analysis on semen and it would be released "shortly".
"In short, it concludes that the risk of Mycoplasma bovis being transmitted through semen is unchanged and remains very low," she said.
Asked if MPI had seen the scientific evidence to back up the assertion antibiotic treatment was effective for M bovis-infected semen, she replied that the answer would be in the review.
Besides the risk analysis, MPI was also investigating how the disease got on to the van Leeuwen farms, but until then no-one could state categorically whether the semen supplied to the van Leeuwens was negative for M bovis.
World Wide Sires general manager Hank Lina said his company believed New Zealand needed its own import health standard. At present people had to take the genetics companies at their word.
"In New Zealand we don't have any commercial labs set up. There's one artificial insemination company that says we've done our own testing and another that says we can't test and another says I can get my bulls tested overseas.
"What is the farmer thinking, does he believe the companies, does he listen to MPI or DairyNZ - there's not many farmers who know what to think, and that's why I think we ought to set up a national standard," Lina said.
LIC said it had confirmed its artificial breeding bulls were free from the disease.
The co-op announced in September it would test for the disease to provide its farmers with greater peace of mind through the dairy mating season.
"We've now completed the testing and I am pleased to confirm that all LIC bulls have received negative test results with no sign of Mycoplasma bovis," chief scientist Richard Spelman said.
Lina said New Zealand's reputation was more important than the commercial drivers of the genetics companies.
"World Wide Sires NZ is putting its hand up to work with the Government, MPI, DairyNZ and other AB companies to work together to agree and implement a set of standards which will provide the reassurance we all need going forward."
MPI's incident controller David Yard said they still had to work out the source of infection at the confirmed infected property and to build a picture of animal movements between all three farms and possible other farms.
M bovis is spread through close contact between animals and through the direct movement of cattle between properties.
MPI's response team was now planning for how the new infected place would be managed and continuing testing of samples from the two other properties.
Lewis called upon Agriculture Minister Damien O'Connor to demand the disease be eradicated, as he had several months ago.
"It's bloody disappointing to see more farms with the disease. It raises questions over how we could handle a more serious disease like foot and mouth."
He noted the criticism by MPI director-general Martyn Dunn of farmers who did not tag their cattle as required, so they could be traced.
"What is the value of Nait if MPI doesn't have confidence in it?" Lewis asked.
Farmers who have concerns can call the Mycoplasma bovis farmer support line 027 444 9380 or their local Rural Support Trust on 0800 787 254 (0800 RURAL HELP).