Police are investigating an attack on three pivot irrigators near Omarama.
Senior Constable Craig Bennett, of Kurow, said the attack caused thousands of dollars worth of damage with 44 tyres on the machine slashed on a property near Broken Hut Rd.
Each tyre was worth up to $800.
He believed the attack occurred sometime overnight between Friday and Saturday and he suspected more damage was yet to be discovered on the machines.
At this point he said the extent of the vandalism could be down to one or several people, but the slashes on the tyres indicate one blade was used.