It's possible 500 sheep found smothered in a narrow gully on a Southland farm were startled by poachers, police say.
Police are now investigating the stock deaths, which happened some time between February 2 and February 3 on a property at Mt Wendon, near Riversdale.
The number of sheep involved and the fact they were found dead in a narrow valley suggests they might have been disturbed on the property.
"It's a possibility that these sheep were startled by someone wasn't supposed to be on the property," Detective Sergeant Greg Baird said.
The stock loss is estimated to be worth thousands of dollars.
Poaching is becoming increasingly common around Southland and police are keen to hear from farmers who see suspicious activity, including out of place people and vehicles.
The sheep incident follows inquiries into illegal spotlighting on Department of Conservation land at Piano Flat.
"These kinds of incidents do break the law and also put the lives of others at risk particularly if firearms are involved," Det Sgt Baird said.