The Department of Conservation (DOC) has fined two Swiss tourists after they were found cycling inside the Tongariro National Park in November.

The couple had their bikes confiscated and were fined $400 each, DOC said.

Video footage showed trampers on the Tongariro Alpine Crossing watching on in bemusement as the two cyclists travelled through the Dual World Heritage park.

DOC Tongariro Operations Manager George Taylor said to get to the point where they were filmed, the rule-breaking mountain bikers had to pass signs warning mountain biking was not permitted, traverse hundreds of steps, go past numerous walkers – while not encountering a single other cyclist.

It is an offence under the Tongariro National Park bylaws (1981) to use a vehicle, including bicycles, off formed roads.

Taylor said their acts were “an affront to those working to protect the fragile environment and cultural significance” of the Crossing.

He said the tourists, who were filmed by trampers, “deliberately disregard the rules and clear communication of those”.

“Bicycles on walking tracks can damage sensitive alpine environments, present a safety risk to trampers, and are generally disrespectful of this taonga national park,” he said.

The bikes were confiscated for a weekend and then returned, a DOC spokesperson said.

Ngāti Hikairo ki Tongariro spokesperson Te Ngaehe Wanikau said the hāpu was deeply concerned to hear mountain bikes had been used to traverse the Tongariro Crossing.

“The use of mountain bikes on a track created solely for pedestrian use, places both the users of the crossing, and the unique environment of Tongariro at risk.

“Ngati Hikairo ki Tongariro condemns mountain biking and any other non-pedestrian activity compromising the safety and well-being of people and Tongariro,” he said.

DOC said had the tourists booked their trip through the crossing, they would have “received confirmation emails containing safety and cultural information to perhaps avoid their embarrassing mistake”.

“Aotearoa New Zealand is precious, and everyone who lives and travels here has a responsibility to look after it and respect its nature, people, and culture,” Taylor said.