Volcanic alert status on Mt Ruapehu moved to 2 last week - the last level before an eruption.
The shift from 1 to 2 happened on Tuesday, GNS Science volcanologist Geoff Kilgour said.
While the mountain is being watched closely, an earthquake 15km northeast of Ohakune on Saturday wasn't asignal an eruption is imminent.
The earthquake of magnitude 3 happened at 2.32am. It was 14km deep. There was another smaller one nearby yesterday at 4.07pm.
The first was on a well known fault, Mr Kilgour said, and there were usually at least two shakes there every week. On some nearby faults there could be 10 earthquakes a day.