Tongariro alpine crossing operators are hopeful the track can reopen by the end of the weekend.
The area remains closed today after an eruption at 1.30 yesterday afternoon – almost four months since a bigger one in August.
GNS scientists are meeting this morning to discuss the situation.
Duty vulcanologist Brad Scott thinks the mountain could still blow its top intermittently for up to nine months.
Air New Zealand says ash cloud from Mt Tongariro is now clearing to the east of the country and its service to Rotorua is recommencing.
However, Taupo and Gisborne airports remain affected and flights to these areas continue to be subject to delays and cancellations. Normal operations are expected to begin as the day progresses.
Airline operations and safety general manager, chief pilot Captain David Morgan, says the airline is working with the relevant authorities to safely make adjustments to flight routes to ensure aircraft remain clear of any ash and keep providing a safe service to the travelling public.
Stewart Barclay from Adrift Outdoor Guided Adventures told NBR ONLINE the track will remain closed today as scientists gather information about the latest eruption.
He says all the information suggests it was a tiny event, limited to about a 200m circumference.
Mr Barclay says while he has had one couple try to cancel because they wrongly thought the sulphur would give them breathing problems, he can continue with his guided walks.
He is taking tourists to other viewpoints or to Ruapehu. And while unable to get to the summit of Ruapehu, he can take them to the skyline ridge.
Last week, GNS warned of an increased likelihood in the coming weeks and months of an eruption at the crater lake.