Police launched an investigation into claims of illegal poaching.
Last month, police concluded there was insufficient evidence to press charges.
But the investigation has been criticised by the farmers involved, locals, Federated Farmers and the independent watchdog group, New Zealand Police Conduct Association for what they perceive as the police officers getting favourable treatment.
There were concerns that local police officers who attended the scene failed to check firearms found in the officers' vehicles and did not confiscate them. Neither officer accused of poaching was formally interviewed at the scene.
Other concerns surrounded delays in the investigation, failures to keep the complainant informed, and then finally the decision not to lay charges.
Now, in a letter obtained by the Herald, the IPCA has confirmed that, after a review of the police file, it has been decided to independently look at the "police investigation in relation to the alleged actions of these officers and their decision making".
An IPCA investigator has been assigned to the case.
Shannon Parker of the New Zealand Police Conduct Association welcomed the IPCA probe.
"There are so many unanswered questions here," she said.
"I trust this will look into the conduct of the staff involved in the original investigation and not just the conduct of the officers at the heart of this."
The farmers at the centre of the claim have taken out trespass orders against the officers involved in the incident.