Warnings are still in place for the summit of Mt Ruapehu because the temperature of its crater lake is unusually low.
In August the Conservation Department asked people not to go within 400m of the lake, or to linger in the bottom of the Whangaehu and Whakapapaiti Valleys, away from public warning systems. Warning signs are still up.
Ruapehu's crater lake goes through heating cycles that last from nine to 15 months and its temperature varies between 15C and 45C, the department's volcanology adviser Harry Keys said.
The lake was at 40C in May when there were tremors but no eruption.
In times of peak heating geyser eruptions can occur.