Jan Hayter, of Tongariro Expeditions, had to wipe 15 bookings yesterday, although inquiries were still coming in.
"The summer's coming and we're going to have lots of tourists that want to come and see the number one volcanic mountain. Wouldn't you want to come and see the mountain that's just erupted?"
National Park Village Business Association chairman Murray Wilson said the number of people visiting the website tongarirocrossing.org.nz increased from about 240 to 2400 in the 24 hours after the eruption.
"When we started getting the first reports of volcanic activity basically it went through the roof."
The Department of Conservation was planning this morning to reopen the Tama Lakes track from Whakapapa Village to Waihohonu Hut and the Taranaki Falls loop, resuming access to some of the most popular day walks to Tongariro National Park.
"We are keen to get people back on to the Tongariro Crossing but we need to make sure the volcano has settled down first," DoC area manager Nic Peet said.
Debris had dammed three small tributaries of the Mangatipua Stream and authorities needed to check whether the build-up posed any risk to downstream bridges and culverts.
With the crossing closed, some tourists instead opted for a day playing in the snow at Whakapapa skifield on neighbouring Ruapehu yesterday.
Irati Maiztegi Landa, from Spain, had been looking forward to tramping on Mt Tongariro until a friend texted news of the eruption.
"I was a little bit disappointed, but now we are planning to go to another place."
Auckland skier Derek Hudson said there had been initial concern among visitors to Whakapapa yesterday, "but now that's definitely gone".
Skifield manager Dave Mazey said besides some school groups deciding not to come, the eruption had had little impact on the ski season.