Experts are advising anyone planning to walk the Tongariro Crossing in the next few months not to go if they don't know how to use an ice axe.
Icy conditions are expected to remain on the world famous walk as it approaches its busiest time of the year.
Tongariro guide Simon O'Neill is gearing up for a busy season of summer guiding, but this winter has seen a wave of walkers taking unnecessary risks.
Mr O'Neill is critical of "those people who don't understand the hazards, who turn up in some cheap runners from The Warehouse, jeans, t-shirts".
"Up here cotton kills," he told 1 NEWS on the mountain track.
Tania Konui of the Department of Conservation has similar concerns.
"It is really concerning if the visitors in front of us are not experienced or not prepared."
The Department of Conservation says snow, ice and sub-zero conditions are likely to stick around, and people looking to experience New Zealand's oldest national park must be well prepared.
"A lot of them arrive unaware of those risks. So by the time we finish talking to them about being prepared and those risks they're booking a guide or choosing an alternate hike," Ms Konui says.
In the last few years DOC has removed summit signage for both Ngāuruhoe and Tongariro. The department says this has helped reduce injuries and people needing to be rescued.
More than 148,000 people walk the Tongariro Crossing every year. But the shoulder season between spring and summer can be dangerous, especially as the numbers peak over the summer period.
Mike Daisley of the Mountain Safety Council has a simple message for those planning a hike.
"You should be carrying an ice axe and know how to use it. And you should be aware of an avalanche advisory. And if either of those two things are completely alien to you - then you shouldn't be going, or you should be using a guide," he says.
And Mr Daisley says if you see snow while enjoying the World Heritage area, it's not too late to stop and turn back.