National Park-based businesses say they have been unaffected by the recent rise in seismic activity at Mt Tongariro.
GNS Science last week increased Tongariro's alert level from 0 to 1, out of a possible 6, after a series of small earthquakes under the mountain. Level 1 means the mountain is showing signs of unrest.
Volcanologist Brad Scott said on average two quakes per year occurred at Tongariro but in the past week more than 20 had been recorded. The quakes were small in magnitude, at less than 2.5, and centred between the Emerald Lakes and Te Maari craters.
Mr Scott said the quakes could be a sign that an eruption may happen in future.
Several tourism operators in National Park told the Chronicle they were not concerned by the increased alert, and it had not affected business.
