Temperatures and gas levels in Mt Ruapehu's Crater Lake remain high nine months after it erupted, and scientists admit further eruptions are possible.
The volcano last erupted on September 25 and GNS Science yesterday said it remained in a state of unrest and was showing unusual activity.
GNS Science volcanologist Michael Rosenberg said the elevated temperature and gas levels indicated the presence of magma in the mountain, but this was not necessarily a sign of an impending eruption.
"This is a natural system [which] you can't really expect to do a regular cycle of heating and cooling, and high gas and low gas."
However, Mr Rosenberg said GNS Science was carefully monitoring the mountain as it did any time there were changes to seismic activity, gas levels or Crater Lake temperatures.
"We have to do that in case these are precursors to an eruption ... It's a natural system and it will do what it will do."
Some gas levels have increased since last year's eruption, and carbon dioxide emissions are now about 10 times higher than typical levels.
The Crater Lake is fluctuating between 34C and 37C, and the alert level for the volcano remains at Level 1, which indicates signs of unrest.
On June 17, GNS Science volcano surveillance co-ordinator Brad Scott said Crater Lake temperatures and gas levels usually followed a predictable pattern of returning to normal after eruptions.
"If further eruptions occur, they may occur without warning," he said.
Ruapehu Mayor Sue Morris said Mr Scott had briefed a council meeting on Friday about the high lake temperatures.
"But as far as I know, there is no danger," she said. "We would certainly know very, very quickly - within minutes - if the mountain was going to erupt."
Mrs Morris said Mt Ruapehu was constantly monitored and robust warning systems were in place.
"So people don't need to be afraid of coming to the mountain ... And of course, it's very, very beautiful to be there right now. There's snow everywhere."
The Department of Conservation, which also takes advice from GNS Science, said it was keeping a close eye on the situation but not changing its directions to the public.
"We're just watching and are curious more than anything," community awareness officer Dave Conley said.
"It's not a state of the mountain that any of the guys have seen, so they're all a little bit curious as to quite what it means."
"Most of the eruptions on Ruapehu tend to come without much warning anyway, so it's a watching brief up there at all times."
Ruapehu Alpine Lifts, the operator of the Mt Ruapehu skifields, was also watching updates and training new staff in contingency procedures.
Last week, Horizons Regional Council emergency manager Shane Bayley called a meeting of emergency management agencies, where they discussed their Mt Ruapehu eruption response plans.
"We identified ways to improve communications between agencies, including councils, GNS Science, Ministry of Civil Defence and Emergency Management, Civil Defence Emergency Management groups, Department of Conservation and police," Mr Bayley said.
"While no predictions can be made about what might happen in the future, based on the unusual levels of unrest on the mountain, it makes good sense to be fully prepared."