The company which operates the Ruapehu ski fields is in a battle with the Department of Conservation (DOC) over who should pay for a warning system to alert people of eruptions and possibly devastating lahars.
Ruapehu Alpine Lifts says it should be the government's responsibility, but DOC says as the company is the biggest operator on the mountain, it needs to step up and cover the costs.
The system is a vital piece of infrastructure that alerts skiers and others on the mountain that they may have just minutes to get to higher ground before a lahar comes flooding through a valley.
Ruapehu Alpine Lifts (RAL) chief executive Ross Copland said it stopped paying in April its 80 percent share of the the system, which costs $62,000 a year.
When DOC increased its licensing fees to operate on the mountain, Mr Copland said RAL stopped paying for the warning system in response.
He said the issue formed part of a much broader conversation with the department about who should pay for what on one of New Zealand's most active volcanoes.
"It's one of those public safety - civil defence - pieces of infrastructure when you're talking about that one specifically. So that's the debate we're having, in the context of pretty significant increases in licence fees."
Mr Copland said it was unclear how much - if anything - a private company should have to pay towards a piece of infrastructure that was there for the wider public good.
"Much like on a beach front or anywhere else, where you've got an early warning system for a tsunami, for an earthquake, for eruption... typically that would be a civil defence piece of infrastructure."
DOC scientific advisor Harry Keyes said RAL had a responsibility to ensure the system was up and running - as did all stakeholders.
"RAL have got a responsibility under the Health and Safety Act to their staff and they've got a moral responsibility to make sure that their patrons are warned if there's a lahar coming down the ski field."
It's one of five systems for warning of danger from an eruption and Dr Keyes said it was probably the most important.
"When Ruapehu erupts the mountain often sends volcanic floods or lahars down valleys and if a person's in that valley then they're at significant risk."
Negotiations between DOC and Ruapehu Alpine Lifts are ongoing, but Dr Keyes said they would find a way to fund the detection system - one way or another.
"The day the eruption detection system is needed it'll be cheap. We're not playing Russian roulette here we are dealing with an active volcano. We've all got a collective responsibility to make sure the eruption detection system is as good as it can be."
Volcanologist Tony Hurst, who has been studying Ruapehu for decades, said the funding situation was a bit worrying.
There remained a constant risk of lahars should Ruapehu erupt again.
"Nearly all the big eruptions have involved lahars [and] about every second or third one causes a significant risk to the ski field."
RAL is a tax exempt company because of its status as a regional promotional body.