An extra four seismic recorders have been set up on Mount Tongariro after a cluster of volcanic earthquakes prompted GNS Science to raise alert levels there on Friday.
More than 20 shakes have been recorded since the middle of July, which GNS says could signal a future eruption.
Volcanologist Brad Scott says the unrest declined during the weekend, but will continue for several months.
He says 10 seismographs on the volcano, plus an extra four portable recorders, have shown volcanic gas levels have increased alongside the earthquakes.
While GNS will continue to monitor the volcano, Mr Scott says there is no threat to public safety.