Update:
Hikers in Tongariro National Park have reported significant rocks falls on the northern side at Mt Ngauruhoe this morning.
The Department of Conservation has released a statement saying there is no indication that the rock fall relates to seismic or volcanic activity.
High rainfall over the weekend has most likely led to rocks becoming unstable on the steep slope, the statement said.
Hikers walking up the flank of Mt Ngauruhoe could also have dislodged several rocks.
GNS duty volcanologist Michael Rosenberg confirmed there was low risk of volcanic activity and an aerial reconnaissance by helicopters had been made to ascertain the cause of the rock falls.
Local police have also been notified of the rock falls.
Hikers are advised to take extreme care if they choose to climb Mt Ngauruhoe.
There is a significant risk of rock fall, especially with large number of hikers on the mountain.
DoC operations manager Bhrent Guy said: "It is better to enjoy the view of Mt Ngauruhoe from the South Crater than take the risk of injuring yourself or others by dislodging or being hit by rocks."
Earlier:
The Department of Conservation is assessing the Mt Ngauruhoe walking track this morning after a rogue boulder fell from above.
A police media spokesman said the incident had been reported to police this morning, though it appeared nobody had been injured by the incident.
The job was handed over to DoC who had sent a ranger from the Mangatepopo Hut to assess the damage, he said.
A spokeswoman at the DoC Tongariro National Park Visitor Centre declined to comment.
The extent of the damage is yet to be determined.