GNS scientists say it is too early to say whether the magma below the surface is bubbling at dangerously high levels within Mt Tongariro.
The Te Mari crater erupted on Monday night and scientists have been carrying out tests ever since to determine the likelihood of it blowing again.
There had been reports and tests carried out showing the magma was bubbling at higher than usual levels, but that cannot yet be officially confirmed.
GNS duty volcanologist Arthur Jolly told NBR ONLINE scientists are constantly reviewing Mt Tongariro’s chemistry, its ash and its rock fragments but they have not established at what level the magma is bubbling.
He says they have geo-chemical data from last night but are still waiting on the analysis of the mountain’s batches of ash.
Magma can either erupt passively as lava flows or explosively as an eruption plume.
The chemistry of the magma, the amount of gas dissolved in the magma and how it interacts with water when it reaches the surface could all determine how magma behaves.
Authorities have kept a close eye on the mountain since the eruption, which closed roads, caused disruption to flights and closed the Tongariro crossing.