The Department of Conservation says it does not know how it will get rid of road spikes planted along a popular track in Te Urewera National Park.
Long nails attached to pieces of wood have been hidden along the tramping and mountainbike track near the Okahu Valley access road.
DoC Rangitaiki area manager John Sutton says protesters are blocking an entrance to the area to highlight the use of 1080 poison and Maori land rights issues.
Mr Sutton says staff trying to work out how to get rid of the spikes once the protesters leave.
He says two of the protesters previously told him they had planted the spikes, but the group now denies it is responsible.
