Rubbish dumping at one of New Zealand's most picturesque lakes was getting so bad there was talk it would be closed off to visitors.
But a Ngāi Tūhoe spokesperson said things are beginning to change, although there is still hostility towards iwi members from some long-time holidaymakers.
"We're getting there, but it's not something that's going to happen overnight," Tamati Kruger said.
In 2017, Ngāi Tūhoe took over management of the former national park from the Department of Conservation, as part of a Treaty settlement.
Kruger, chairman of the Te Urewera Board and Tūhoe Te Uru Taumatua, said the iwi was "astonished" at the severity of the dumpings and vandalism at Lake Waikaremoana during 2019.
A Waikaremoana Holiday Park spokeswoman told Stuff the park's entire team had recently collected "quite a few tonnes" of rubbish, and disposed of it.
Although the situation was improving, Kruger said they were still facing the rubbish issues and hostility from campers who use Te Uruwera land.
"November/December was the beginning of our summer year, so we'll probably have a better assessment of things in March. We're not on top of it, but there has been some significant improvements."
Kruger said many holidaymakers still continued to treat Te Uruwera "like a national park down the road" and took "a lot of stuff in to have a good time".
He said plastics and bottles were some of the major concerns when it came to littering.
"Because we don't wear a uniform or anything like that we get a lot of push-back from tourists, particularly those who have been using the park for a long time.
"We are confronting three or four generations of practice that has become normalised and we don't want to come across as the new policemen.
"Many of them have not heard that there's been changes to Te Uruwera and these changes happened five years ago."
Kruger said it was mainly New Zealand campers who were hostile.
"It's just basic human common sense that you don't litter. When the Department of Conservation was around they'd put rubbish bins everywhere, which encourages bringing in more stuff.
"We took those bins away and people said, 'Well what do we do with our rubbish?'
"We said, 'Well put it back in your car and take it home'. So the initial reaction was people just left their rubbish there."
Kruger said Ngāi Tūhoe was working with DOC on upgrading park notices and websites to communicate messages and regulations to tourists.