The Palmerston North Armed Offenders squad were called to an incident around 9pm last night at the Waikawa camping ground, south of Levin.
There were reports of a disagreement between some of the campers, with one camper allegedly having a knife and threatening others.
One of the campers had also allegedly fired shots from an air rifle.
When police and the AOS arrived, they located two air rifles and a machete.
Police detained one man who is now assisting police with their enquiries.
Paramedics treated one camper for a laceration to his eye.
More information is expected later this morning.
3 News.
