Tongariro Alpine Crossing hikers will have to make haste through the national park if they don't want their cars to be clamped.
The Department of Conservation (DoC) has introduced a four-hour parking restriction at the beginning of the walk, in an effort to reduce overcrowding.
Instead, hikers who plan to walk the entire Alpine Crossing can park at the Mangatepopo carpark and catch a shuttle, which costs $30 per adult and $25 per child.
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DoC says vehicle overcrowding is at the point that it has impacted the enjoyment factor of the walk.
Walkers can still park at the end of the track, and can still park at the beginning to go on short walks for less than four hours.
The full Tongariro Alpine Crossing is 19.4km long, and takes on average between six and eight hours to complete.
Operations manager Bhrent Guy said the four-hour time limit is long enough for people to complete the short walk to the end of the Mangatepopo Valley.
Mr Guy hoped the restriction will "discourage people leaving their vehicles at one end and walking the Tongariro Alpine crossing and the ferrying around the mountain to the start again".
"It multiples the traffic volumes and clogs up access for others. There is also a concern that vehicle congestion will reduce access for emergency services," he told Newshub.
"The Tongariro Alpine Crossing is a unique day alpine hiking experience and that experience should start with a relaxing shuttle to the track and back home safely, not with worrying about parking."
The parking restrictions will run through the busy period, from October 21 until April 30 2018.