Mt Ruapehu could have a minor eruption within the next four weeks, according to volcanic monitor GNS Science.
Volcanic tremors and temperatures at Mt Ruapehu's Crater Lake, Te Wai ā-moe, have decreased in the past week.
But GNS Science reported gas emissions were still high and as volcanic unrest at Mt Ruapehu continues, the "potential for eruptive activity" remains the same.
GNS Science duty volcanologist Yannik Behr said the last gas measurement flight, on May 13, confirmed there were high levels of sulphur dioxide and carbon dioxide at the lake.
"Continued emission of sulphur dioxide [shows the] gas was released from shallow magma and suggests the volcano is still at a heightened level of unrest.