As tourist numbers soar, concerns have grown about how the Department of Conservation (DOC) is meeting its dual responsibilities to look after visitors and protect the environment.

Parliamentary Commissioner for the Environment Dr Jan Wright put the problem succinctly in a May report: "Only a fifth of our bird species are secure, and a third are in serious trouble. The situation is similar for lizards, frogs, insects, and other native fauna."

International tourists numbers were projected to double in the next five years, increasing pressure on tracks, bridges, huts, visitor centres, toilets, car parks, and other infrastructure.

Fears are growing for the future of the kea, the world's only alpine parrot, as predators take a toll on the birds.

Protection of people visiting a national park would always trump biodiversity protection, Wright said.

READ MORE:

* Tourism may be too much of a good thing for overwhelmed New Zealand

* NZ's fragile mountains: Sacred places under threat

* Native birds in 'desperate situation' with 80 per cent threatened - commissioner

* Greens promise to double DOC funding and rangers against 'waves of predators'

* NZ ill-equipped for 5 million overseas visitors

Early in 2017, a norovirus outbreak swept through a popular tramping route in Nelson Lakes. Every hut and toilet on the track was disinfected, while helicopters were needed to reach remote areas.

TOM PULLAR-STRECKER/STUFF Tourists stream across the busy Tongariro Crossing on Easter Sunday, when queues for toilets stretched to the dozens.

"While this had to be done, it would have diverted resources away from activities like predator control," Wright said.

'HUGE PRESSURE' FROM TOURIST NUMBERS

Among those unhappy with what they consider happened to DOC's direction under the previous government is Forest and Bird. The environmental group's chief conservation adviser, Kevin Hackwell, said the department was under huge pressure to deal with the rise in tourist numbers.

DASHA KUPRIENKO/Stuff.co.nz Queenstown residents discuss the pros and cons of living in a town which is one of the country's hottest tourist destinations.

"Their mandate is to protect our biodiversity. The legislation they work under says very clearly that is their primary function. Supporting recreation and tourism is secondary and should only be allowed if it doesn't interfere with that primary function," he said.

Forest and Bird expected DOC would refocus on its core responsibility under the new Government, in which Green MP Eugenie Sage is Minister of Conservation.

Asked what DOC could expect, Sage pointed to the confidence and supply agreement between Labour and the Greens. The deal talks about "significantly increasing conservation funding", but Sage was not forthcoming on what that would mean.

ENVIRONMENT CANTERBURY A DOC ranger working on the control of lupins in the upper Waitaki Basin.

"The size and details of any increase is currently under consideration and is a matter for Budget 2018," she said.

"My first priority is to address the biodiversity crisis which has seen more than 3000 native species listed as threatened, and ensure DOC has the funding and resources it needs to achieve this goal."

The department also had to fulfil its statutory role to advocate for nature through the Resource Management Act process, "something which was not encouraged by the previous government", Sage said.

DAVID HALLET/STUFF An endangered Black Stilt, or kaki, released at Lake Tekapo after being bred in captivity at Twizel.

"DOC must also invest in visitor facilities on its own land both to protect intrinsic natural values and ensure visitors are able to enjoy them safely."

DOC BUDGET INCREASE

DOC's departmental budget increased by about $18 million in 2017-18, climbing to $376m, with the department saying 47 per cent of that was for biodiversity and 39 per cent for recreation.

BUBS SMITH/DEPARTMENT OF CONSERVATION Whio in Ruahine Forest Park, which has a predator trapping programme.

The Government provided about $21m in each of 2015-16 and 2016-17 for what was called the Battle for our Birds, a new operation trying to fight an explosion in rat and stoat numbers as a result of heavy seeding, or mast, in beech forests.

Former environment commissioner Wright said there was also a mast in 2014, when about $20m was spent on the Battle for our Birds.

"That battle was fought using cost-effective 1080, but it was only fought over 16 per cent of the area of forest that was masting and causing rodent and stoat populations to soar," Wright said.

LIZ BROWN/DOC/SUPPLIED Fourteen-day-old kaki chicks, raised in DOC's Kaki Recovery Programme in South Canterbury, find their feet.

To control predators in all masting forest in 2014 would have cost about six times as much. In warmer, more fertile forests such as in Northland, rat numbers were high every year.

Annual visitor numbers at the Tongariro Alpine Crossing (TAC), and at Aoraki/Mt Cook National Park show how demand for recreational opportunities on the DOC estate has soared.

DOC figures show 45,000 people visited the TAC annually 10 years ago. By 2016-17, the number was 125,000 – almost all in the warmer months between October and May. That's a consistent compounding annual growth rate of about 10 per cent.

BRADEN FASTIER/Stuff.co.nz Project Janszoon and the Department of Conservation have launched a breeding programme for northern South Island kaka to improve the genetic diversity of the native parrot being introduced to Abel Tasman National Park.

"This season has so far seen consistent high walker numbers with people taking advantage of the fantastic summer weather to walk the track," DOC recreation tourism and heritage director Gavin Walker said.

SEASONAL PARKING RESTRICTIONS

Changes made this season to maintain the special values of the TAC included the introduction of seasonal parking restrictions at either end of the crossing, with walkers being encouraged to use shuttle services from nearby towns.

Extra toilets had been put on the track for the busy summer period, there were more parking wardens and a new advocacy manager was providing information to walkers. A review was under way looking at the visitor, cultural and environmental values of the experience, along with the TAC's local and national economic contribution and importance.

Visitor numbers at Aoraki were estimated at 840,000 for 2016-17. That was based on vehicles entering the park and did not include those arriving by air, Walker said. International visitors were thought to be up 15 per cent from the 2015-16 year.

In the past decade, DOC spent more than $10m on infrastructure at the national park, including upgrading Tasman Valley Rd, the visitor centre and Hooker Track, and providing more toilets and shelters.

More rangers were at the park this summer to interact with visitors and carry out compliance checks at campsites and huts, and work was planned on toilets and popular tracks.

"We are seeing record numbers of international and domestic visitors to the outdoors as more people want to connect to our nature," Walker said.

About 3.7m New Zealanders visited public conservation areas – from national parks to marine reserves – at least once a year, as did 1.4m international visitors. The average increase in international visitors to all 13 national parks last year from a year before was 12 per cent.

More than $2m was planned to be spent on prioritised pressure points for this summer season and into next year. An extra $76m over four years was included in the 2017 Budget to manage increased visitor numbers.

"While some key sites are under pressure from tourism, most places on public conservation land have the capacity to accommodate more visitors," Walker said. "DOC is focusing on dispersing visitors to reduce pressure at key sites and maximise the benefit generated from less used visitor assets."

For example, DOC was marketing a new set of short walks and day hikes to encourage people to visit new places.

FREEDOM CAMPING

DOC also has some challenges dealing with the vexed issue of freedom camping, which is allowed on public conservation land unless expressly restricted to self-contained vehicles, or prohibited.

The list of prohibited or restricted areas is long, with several more added from December 1. Three of those places were in the Taupō district and, in a statement explaining the move, DOC said the sites did not have the facilities to support the high number of day visitors and influx of campers.

Tourism growth, particularly the rise in non-self-contained freedom campers, meant some sites initially open to campers had to be reconsidered because of the increased pressure, DOC said.

"The department only wishes to control freedom camping where it is causing real problems or where the issues cannot be managed in another way."

Forest and Bird's Hackwell considered part of the problem went back 15 years – beyond the time of National-led government, to when Labour was in control.

During the past 15 years, DOC had been severely restructured many times, Hackwell said. One result was that many fewer rangers were on the ground.

An example of DOC feeling the pressure of growing numbers of tourists – "feeling they couldn't say no" – was a decision to allow a big increase in the number of helicopter landings on the Ngapunatoru Ice Plateau in Fiordland.

The Fiordland National Park Management Plan put a limit of 10 helicopter landings a day on the plateau, but from August 2016 a potential 80 landings a day has been allowed – 10 landings per day for each of eight operators.

DOC said the move was a trial, and figures to the end of April show the highest number of daily landings was 34, which happened twice. Operators pay fees to land on glaciers on public conservation land.

Federated Mountain Clubs president Peter Wilson said his group had taken the Ngapunatoru issue to the Ombudsman, who was expected to report "any day".

The increase in potential helicopter landings had happened under the previous government. "Hopefully a new government will be able to fix it up," he said.

BORDER LEVY PLEDGE

Former commissioner Wright and Forest and Bird's Hackwell are both keen on a border levy on international visitors to help pay for biodiversity protection and restoration.

Such a levy was part of Labour's election policy, which proposed a $25 per visit levy on international visitors who were not citizens or residents of New Zealand.

It would be used for a $75m annual tourism and conservation infrastructure fund, of which $45m would go to tourism and $30m would be used for biodiversity.

Tourism Minister Kelvin Davis said he was working with officials on a range of potential funding options, including a levy, for tourism infrastructure.

"We need to address the extra demands on facilities that are used by both visitors and residents, particularly where there are fewer ratepayers."

* Comments on this article have been closed.