October

Crowds have flocked to the central north island to witness the aftermath of the eruption of one of the world’s most active volcanoes.

Thousands of enthusiastic sightseers hit Mt Ruapehu’s slopes just two days after last week’s eruption which spewed debris five thousand metres into the sky and triggered two lahars.

The mountain, which sits in the middle of the North Island, is home to two of New Zealand's largest commercial skifields, Whakapapa and Turoa and is the highest point in the North Island.

The eruption occurred without warning and generated a 2.8 magnitude volcanic quake. Pilots flying in the area reported an ash column of about 5000 metres.

It caused the evacuation of ski lodges on the mountain which were full due to school holidays. It also prompted a rescue operation after a tramper had his legs crushed by debris.

It was described as a 'blue-sky' eruption, coming without warning, and going from nothing to full-on in about a minute.

Mt Ruapehu's last major eruptions occurred in 1995 and 1996 and just last year the tephra dam, which had been holding back the crater lake burst, sending a lahar down the mountain.

New Zealand has a number of active volcanoes including Raoul Island (Kermadecs), Mt Taranaki and White Island.

The upper mountain, above 2000 metres, remains out of bounds as Department of Conservation officials assess the damage.