"We are awaiting further turf analysis tests but have been advised that the cause of the damage is due to the inadvertent application of a herbicide.
"We suspect that the introduction of this substance was intentionally done so by a third party."
The owner and staff are said to be devastated by what has occurred on their course.
The condition of the course is not expected to be healthy again until spring, forcing the club to reduce the green fee to $100 per player.
Found off the Thermal Explorer Highway, north of Taupo, the green fees for a registered New Zealand golfer is usually $165.
Set midway between Auckland and Wellington, the course was built by the New Zealand Government and officially opened in 1970.