It's shaking all over, and generating some hot stuff, but a volcanologist says it's way too soon to tell what's next for Ruapehu.

The crater lake has been heating up and volcanic tremor signals are at their most intense in nearly a decade.

However, GNS volcanologist Brad Scott says most of Ruapehu's latest behaviour is not unusual.

He says the crater lake's been heating up since mid-December, and it's a pretty long-term process.

Mr Scott says GNS has a Volcanic Alert Level 1 in place, indicating only "minor unrest."