A Far North marae is urging people to keep their motorbikes and four-wheel-drives off the dunes at two popular beaches, before they are damaged irreparably.
Last week signs instructing riders and drivers to stay off the dunes were erected at entry points to Tokerau Beach and Puwheke Beach, on the Karikari Peninsula, by local hapū Te Whānau Moana and Te Rorohuri.
Haiti-tai-marangai Marae chairman Thomson Lawrence said the decision had been made after years of concern about increasing erosion of the dunes and damage to wāhi tapu. People had been taking vehicles into the dunes for about 30 years, but the problem had worsened as four-wheel-drives had become more common and more powerful.
"At one time these dunes were covered in all sorts of greenery and grasses. Now it's getting to the stage where they will end up as a desert," Mr Lawrence said.
The hapū had erected the signs on Wednesday last week, and while vehicles had been heard "roaring around in the dunes" over Easter, it was too soon to say how the public would respond.
Mr Lawrence expected most locals would support the "common sense" measure, although vehicles came from as far away as Kerikeri and Kawakawa, and there were no plans for a rāhui, or formal ban, at this stage.
"We'll try signs and Facebook first ... If people don't respect it you can't say we didn't try. Then we'll take it to another level," he said.
Further steps could include signs on the dunes themselves, replanting to help the dunes recover, and even blocking vehicular access.
"I've kicked a lot of people out of there over the years, and I'm over it," he added.
"You can't be up there all the time. It's a total lack of respect for a place where there's wāhi tapu and koiwi (bones)."
Te Runanga-ā-Iwi o Ngāti Kahu chief executive Anahera Herbert-Graves said the iwi "absolutely" supported any measures hapū took to fulfil their obligations as mana whenua.
Last year west coast iwi Te Rarawa went a step further by fencing off about 4km of dunes it owns at Ahipara, and along 90 Mile Beach, blocking vehicle access to some of the most vulnerable dunes, as well as middens and other sites of cultural importance.
Construction of the fence prompted a Whangārei off-road enthusiast to organise a "truck and bike day to take back the Ahipara dunes", but local residents closed the road that leads to Te Kohanga and Tauroa Point, and in the end only a few bikes turned up.
Mr Lawrence said the cost of putting up fences along Tokerau Beach would be prohibitive, but he believed that some of those who used to frequent Ahipara's dunes were now targeting the Karikari Peninsula instead.