St John central communications spokeswoman Jess Miller said an ambulance had taken a person to Palmerston North Hospital with moderate injures. They received the 111 call at 10.34am Tuesday morning and sent one ambulance.
A hospital spokeswoman said the man was in the emergency department in a stable condition.
Manawatu District Council communications manager Paul Stein said the campground is managed by the council, but said the council had no detail about what had happened there.
Inspector Borrell said nobody else was injured and there was no risk to the public.
Vinegar Hill, or State Highway 54, on the banks of the Rangitikei River, is a scenic route about 5km north of Hunterville.
The campground is noted for holding a gay new year's eve event which attracts hundreds of people.