Tongariro eruption: Key facts

Mt Tongariro's on heightened alert after its first eruption in 100 years.

The eruption's described as small and was centred at the Te Maari craters.

People living near Lake Rotoaira, at the southern end of Lake Taupo, reported the eruption to police about 11:50pm last night.

Tongariro's activity alert has been raised from one to two on a scale with the highest number five - that means a small eruption is underway.

The Civil Aviation alert has been raised to red, telling pilots there is ash being thrown into the air.

GNS Duty Volcanologist Michael Rosenberg says there's no connection between the eruption on Tongariro and the increased activity at White Island.

Roads reopened

The section of State Highway One between Rangipo and Waiouru and State Highway 46 across the northern face of the mountain, west of Rangipo have reopened

Evacuations

Civil Defence has not ordered any evacuations but a number of families have voluntarily left their homes.

Taupo District Council emergency manager Phil Parker says until they know more, there's no need for residents to evacuate.

Ash

Ash has fallen and is up to five centimetres deep in some areas near the mountain.

Civil Defence says a sizable fine ash cloud is dispersing across Hawke’s Bay, and particularly in the north-west of the region.

A layer of ash approximately one millimetre in depth has fallen inland from Napier and north-east into the Wairoa area.

There's also a noticeable sulphuric smell in the air around Napier-Hastings.

Civil Defence spokesman Vince Cholewa says ash could reach those living in Waikato, Hawke's Bay, Gisborne, Manawatu-Wanganui, Bay of Plenty and Taranaki

There's also reassurances there's no health risk to the wider community as a result of ash from the eruption.

Police say currently the risk is only minimal and confined to people in the vicinity of the eruption who may suffer from respiratory issues. 

Water

Health warnings are being issued to residents in the central North Island following the eruption on Mount Tongariro overnight.

Inspector Brent Crowe says locals need to check their water supplies to check they're not contaminated, and disconnect tank water connections.

Flights

Flights are gradually getting back to normal, as the Tongariro ash cloud clears to the east of the country.

Air New Zealand says services are recommencing to Gisborne, Rotorua, Taupo and Palmerston North.

But flights to and from Napier are still subject to delays and cancellations.

Chief Pilot Captain David Morgan says Air New Zealand's will make adjustments to flight routes to make sure aircraft stay clear of any ash.

Skifields

Wind is blowing ash in the opposite direction of the ski-fields, meaning Whakapapa and Turoa remain open.

Mountain Manager Chris Thrupp says they'll be keeping an eye on the situation and they haven't been advised they should do anything other than operate normally.

Post

There will be no mail deliveries in parts of Hawke's Bay today due to Tongariro's ash cloud.

Posties in Napier, Hastings and Waipukurau are taking on board Civil Defence's warning to stay inside as ash from the mountain disperses across the region.

New Zealand Post spokesperson Jaimee Burke says the safety of posties is the company's priority.

Deliveries will resume once conditions clear up.

Photo: NZ Herald