A Dunedin landowner has blocked Ospri staff from carrying out possum control on his land, claiming the company is harassing him and being "a nuisance".
But the pest control company says it is allowed on the property and the work is critical to ensure a tuberculosis (Tb) outbreak is prevented in the area.
Police were called to Adrian Black's Sawyers Bay property about 9.30am after Ospri staff were confronted by Black and about 20 others who also opposed Ospri's work.
Black grazes sheep and has an area of native bush on the 7ha property on Upper Junction Rd.
Ospri has visited his property three times previously as a part of its Tb free programme, which aims to eradicate bovine Tb by carrying out possum control.
Yesterday was to be the company's fourth visit.
Black said he had concerns about the need for the programme and its effectiveness.
He said he asked the company not to come to his land until he had time to consider answers he received late last week to a series of questions he had asked of Ospri.
The company, however, told him it would be there at 9am yesterday, because "I had no rights as a private property owner to stop them", Black said.
When two Ospri staff members and a security guard arrived, protesters blocked their ute with a car so the ute could not drive up to the gate of the property.
Shortly after, four police officers arrived. They spent about an hour talking to both parties.
Ospri did not attempt to enter the property.
Black opposed the work because he did not believe Tb among possums was a significant issue and felt some of the information he was provided late last week supported his doubts.
That included data which showed, between 2003 to 2021, 114 possums out of 92,536 possums caught by Ospri had Tb, and that there was no proof the individual possums taken in surveys by Ospri had infected cows with Tb, he said.
The Ospri information also said, however, most surveys were deliberately carried out in order to confirm an expected low infection risk, therefore, it was wrong to infer that those findings represented a typical or average disease prevalence in possum populations.
Black said he felt Ospri was exceeding its authority and that there was not enough government oversight of its work.
He believed people should be allowed to enjoy their own private property "free of nuisance, free of harassment and free of trespassers".
He said he had trespass notices to stop Ospri staff coming on to his property, but an Ospri spokeswoman said those were retracted by police.
The animal disease management agency is allowed, under the the Biosecurity Act 1993, to enter private property and conduct pest control operations in order to reduce Tb.
Ospri service delivery general manager Vivienne Larson said it had exhausted all options since formally notifying Black in December 2019 of a proposed possum control operation on his property.
It was disappointing not to be able to resolve the land access issue, she said.
Pest control contractors were ready to go on the property and deploy caged traps, but did not feel confident enough to undertake the work, and even with police presence a decision was made to postpone the operation.
Ospri worked with about 300 landowners in the area and the majority were supportive of the Tb programme, she said.
The work was required on the farm because there had been a Tb outbreak in the area and an infected possum was found nearby, so it needed to be cleared to ensure the area was Tb free.
". . .so we are not undertaking it without a lot of genuine concern and a genuine reason."
A police spokeswoman said a meeting was scheduled between those involved or later this week to attempt to resolve the matter.
All parties had left the scene by about 10.50am.
Police could not offer further comments for privacy reasons.