There is growing concern someone could be killed on Otago's bike trails in a collision with virtually silent high-powered e-motorcylces illegally using the tracks.
E-bikes with pedals and motors up to 300W are allowed on the tracks, but not the more powerful e-motorcycles.
Mark Williams of the charitable trust Queenstown Trails, responsible for planning, developing and maintaining the trail network in the Whakatipu Basin, said there had been several frightening incidents involving e-motorbikes on the network.
He said the bikes were quite heavy - up to 85kg - and could go "upwards of 50, 75, 100km/h".
"And they're silent, they're really quiet, so they're surprising people on the trail," he told Checkpoint on Monday.
"There have been incidents of collisions. There was one last week over in Australia… collided head-on with someone cycling down the track."
Listen to the full interview with Mark Williams of Queenstown Trails here
E-bikes are growing in popularity, and they are much slower and less dangerous to other riders than e-motorbikes.
An e-bike still requires users to pedal, and just gives them a bit of a boost; while e-motorbikes are powered solely by the engine, just like a traditional motorbike. Anything 300W in power or above is legally considered a moped, so not allowed on cycling/walking trails.
Their speed and weight meant they caused significant damage to the trails, Williams said.
As for whether it was ignorance of the rules, or a feeling the rules did not apply to them, Williams suspected a bit of both.
"I think … because they're e-motorbikes, people are trying to consider them e-bikes, and therefore think they're permitted on local walking and cycling trails, which of course isn't the case…
"People are using the fact it's an 'e' motorbike as an excuse to be able to ride it wherever they want… I don't think it's the bike community. I think potentially it's a new group of users coming in."
While normal motorbikes made their presence known via noise, e-motorbikes did not.
"You don't get any warning. If you come around a blind corner and there's someone coming at you upwards of 50km/h, that's a real problem," said Williams.
"Nobody wants to say 'don't ride e-motorbikes'... but please, not on the public trail network."