The Department of Conservation has initiated an independent review of a 1080 drop in which cows were killed.
DoC says it is taking the "extraordinary step" to provide public confidence in its operations.
Eight cows were found dead on a King Country farm following DoC's Mapara 1080 helicopter drop on private and conservation land on September 6.
Toxicology results on two cows confirmed they had ingested fluoroacetate (1080), after they broke through a fence to get into the operational area.
DoC said initial investigations of the site, permissions and communications documents and helicopter flight data indicated DoC had undertaken the operation as planned and cattle did not have access to 1080 bait on the farmers' paddocks.