Ruapehu crater lake advisory lifted

Mt Ruapehu's 1995 eruption affected farms across the central North Island. Photo/ File

The Department of Conservation has cancelled an advisory originally issued in August, for people to take extra caution trekking up to Ruapehu's Crater Lake.

Cooling temperatures in the Crater Lake in August had created uncertainties about the state of the vent system under the lake. As a result of this, DOC noted that there was a small chance a minor eruption might occur and recommended to climbers, and others visiting the summit area, that they should minimise their time in this area and in the upper parts of valleys on the mountain.

Subsequent monitoring by GeoNet and GNS Science, including sampling and analysis of water and gas from the Crater Lake, have clarified the situation.

Measurements also show that the temperature in Crater Lake has now warmed a few degrees.

"The monitoring data are reassuring and consistent with what we have learnt about Ruapehu in the last 20 years" said Dr Harry Keys, technical advisor-volcanology at DOC.

"However, we have also learnt Ruapehu continues to be one of the more unpredictable volcanoes, which is why we issue such advisories when there is extra concern for public safety."

The volcanic risk advisory signs, erected with the support of iwi, have now been removed from around the volcano.

Normal operations continued for visitors to all areas outside the summit craters and upper valleys during the Advisory. "Operations at all three ski areas, roads and areas surrounding the mountain were not affected," conservation services manager Paul Carr said.

DOC recommends no-one ever camps within a kilometre of the Crater Lake.

The level of unrest at Mt Ruapehu is continually monitored by GNS Science.