Here's how the day unfolded after the Mount Tongariro eruption.
- Mount Tongariro erupted at around 1.30pm
- Volcanic Alert Level raised from 1 to 2
- Eruption lasted five minutes
9.04pm: Tune in to TV ONE's Breakfast tomorrow for the latest news on Mt Tongariro, where host Rawdon Christie will be crossing live.
8.02pm: Mt Tongariro is continuing to puff out a cloud of ash and steam this evening, nearly seven hours after erupting.
6.45pm: All hikers are now safely off Mt Tongariro after this afternoon's eruption.
6.04pm: ONE News reporter Daniel Faitaua said GNS Science cannot rule out whether heightened activity at Ruapehu's Crater Lake contributed today's eruption.
5.46pm: All roads are open in the Tongariro area, however drivers are being told to exercise caution.
5.28pm: GNS Science says activity on the mountain has decreased, downgrading the Aviation Colour Code from Red to Orange. The Volcanic Alert Level remains at 2.
5.20pm: Jetstar communications manager Phil Boeyen said no Jetstar flights had been cancelled, however there were some delays while they assessed the situation.
5.16pm: Livestock are not expected to be affected by today's eruption, however the NZ Veterinary Association warns if the situation gets worse there may not be enough water and clean feed available.
4.56pm: Leola Abraham from the Taupo District Council said the Department of Conservation put a helicopter up to look for people still on the mountain. She said DoC was still working to remove staff from Tongariro.
4.46pm: Gulf Harbour School Principal John Petrie said there were levels of apprehension after the eruption, but that the 20 Year 8 students felt safe.
"It's an experience I don't think our children will ever forget."
4.37pm: ONE News reporter Ruth Wynn-Williams said a huge column of ash is still coming out of the crater even though the mountain is no longer erupting.
4.30pm: Ash is expected to fall downwind of the mountain in the Waikato, Hawkes Bay and Bay of Plenty.
4.12pm: Area Commander Inspector Steve Bullock is reiterating a message for people to stay away from the volcano to avoid "unnecessary congestion" in the area.
4.01pm: State Highway 46, the road leading up to the mountain, is the only road affected by the eruption.
3.38pm: A group of 20 Year 8 students from Gulf Harbour School were also on Tongariro when it erupted. Deputy Principal Jane Cochrane said all the children were safe.
ONE News flew over the crater shortly after today's eruption.
3.26pm: Air New Zealand says flights operating to some airports east of Mount Tongariro may be delayed or cancelled as a result of the eruption. Find if your flight has been delayed here.
3.13pm: A group of around 45 walkers with Adrift Outdoors are heading out of the area.
3.08pm: Tamatea Intermediate Principal Roy Sye said children were on a field trip eating lunch when the mountain "blew up".
"We had plans in place because we knew there was heightened risk."
3.04pm: Airways NZ said it will work with airlines to ensure flight paths are well above or around the ash and steam coming from the eruption, and said the cloud seems to be moving quite quickly.
3.01pm: Around 50 people are thought to be doing the Tongariro Crossing, and DoC spokeswoman Kim Turia said access roads to the mountain have been shut.
2.55pm: A group of school children on the Tongariro crossing are safe.
2.52pm: There have been no reports of injuries.
2.51pm: Sam Kennedy, who was filming in the area for Australian Geographic, said it was "pretty surreal". He said there was no noise or shaking of the ground before it erupted.
2.43pm: Senior Volcano Geophysicist Steve Sherburn said the eruption went on for about 5 mins. The ash went 2 or 3km above the crater before it drifted north-east.
"One of the key things is there was absolutely no warning of this the seismic stations we have monitoring Tongariro showed no activity before the eruption at all."
Sherburn said there are no volcanic patterns emerging because nature seems to be "throwing us curve balls at the moment".
2.34pm: Air New Zealand said on Twitter the eruption was not causing delays at the moment.
We do not currently expect delays/cancellations to our domestic services as a result of Mt Tongariro eruption based on info at this time.Air New Zealand (@FlyAirNZ) November 21, 2012
2.40pm: Here's the Civil Defence information for a volcanic eruption.
2.31pm: Ash from the eruption is beginning to hit the ground.
2.25pm: Ed Swift tweets: "Don't worry, it's just Peter Jackson putting the last touches on #TheHobbit.
2.32pm: Taupo Civil Defence is responding to the eruption to ensure anyone on or around the mountain is safe.
2.25pm: A b us company has confirmed about 100 teachers and children from Tamatea Intermediate are about two hours into the tramp on Tongariro track. Bus drivers are waiting for children to come out.
2.19pm: Resident Dieter Erasmus told ONE News the plume was up to 6000 metres high.
2.05pm: Emergency Response NZ quotes Air New Zealand CEO Rob Fyfe as saying the eruption " is not having a significant impact on our operations at this stage".
1.55pm: Civil Defence has advised people to visit civildefence.govt.nz or follow @NZcivildefence on Twitter for Ministry of Civil Defence information on the eruption.
1.50pm: On Twitter, Lynne Pope (@elpie) wrote: " A gorgeous, sunny, blue-sky day in paradise, except, of course, where Mt Tongariro is erupting nasty grey cloudy stuff into the sky.
1.45pm: Volcanic Alert Level has changed from 1 to 2 and the Aviation Colour Code has been upgraded from Yellow to Red.
1.40pm: Robert Coup (@amatix) tweets: "Tongariro erupting. Classic bait-and-switch by NI volcanoes", in reference to Mt Ruapehu being on alert.
1.35pm: A picture from the website shows ash and smoke billowing out of Te Maari Crater , the same crater that erupted on August 6.
1.30pm: GeoNet reported Mt Tongariro has erupted.