Continued vandalism at Waipoua Forest Lookout Tower is causing major concern for the Department of Conservation.
In a recent attack, a gun was used to shoot out the windows - the third time in the past six months the windows of this historic building , a popular visitor site, have been smashed.
DOC spokesman Tony Maidment said: "It is alarming to sight this type of behaviour occurring. The community need to be aware of this type of activity for their own safety."
He said the damage to the tower would mean that for the third time money would have to pulled from other budgets to effect the repairs.
This was money that could otherwise have been used on projects that would benefit the wider community, he said.
According to a Historic Heritage Assessment report completed by the department in 2010, the tower is thought to have been built around 1950-51.
Nationally, the lookout represents an important aspect of work carried out by the New Zealand Forest Service, and is the only fire lookout in the North Island managed by the Department of Conservation.
The tower provided housing and work equipment for a person known as a "fire lookout," whose duty was to search for signs of fires in the forest. Lookouts were posted during fire risk season between October and April.
With panoramic views of the forest, the Waipoua tower is located on a high point to maximise the viewing distance and range.
It is regionally significant because it symbolises the early protection of the Waipoua Forest - the largest remaining native tract of forest in Northland.
Still in good condition, a unique feature of the structure is the compass ticks around the inside upper window sash. These were used to take bearings on fires and are still well preserved.
It is also of cultural significance to the region and to the people and families of those who worked there. "Places like this are special to us and we must protect it for the benefit of future generations," said Mr Maidment.
If anyone has any information on the vandalism or has noticed anyone deliberately damaging property at other historic sites, please contact the local DoC office or phone Dargaville police on 09 439 3400.