WAITOMO - Residents and cave operators at Waitomo want the Department of Conservation to ban commercial caving in one of New Zealand's largest caves.

The part-owners of the Gardners Gut cave, Paul Letica and Karan Frederikson, have land above it and say it has suffered the equivalent of hundreds of thousands of years' worth of damage in the past 10 years.

The 13km cave, located in the Ruakuri Cave system, is the longest in the North Island and the Speleological Society classifies it as nationally significant. It runs under other farms and some department land.


Mr Letica said the department should ban commercial caving and control access to sensitive formations inside Gardners Gut, especially fragile environments in the Zweihohlen section and the Henry Lambert section.

Large, "unruly" groups had open slather. Rock formations including massive stalagmites were damaged and mud was being trekked through the cave.

"It's a real mess and disgrace. The cave is not an endless resource. The damage is irreversible and the rehabilitation process is slow."

The department's King Country manager, Ray Scrimgeour, said most of the damage happened in the decade after the cave's discovery in 1957.

DoC manages most of Gardners Gut, which is rated as one of the most popular recreational caves in the country.

"You can't lock up every cave," Mr Scrimgeour said. "It is better that the public has access to a cave which has already been weathered by traffic and tighter restrictions are placed on untouched caves."

But a 1998 earth science masters thesis on the impact of recreational caving stated that the significantly increased use of the Zweihohlen and Henry Lambert sections since commercial adventure tourist trips began in 1980 had damaged them.

Waikato University student Benjamin Bunting suggested that management changes were needed to ensure that the impact of visitors was at an acceptable level.

Mr Bunting concluded that most sections of the studied area were "moderately or severely impacted" by recreational use. The most severe impacts were on the cave floor, and could have been reduced "had trails been defined [using flagging tape] within this cave prior to extensive recreational use."

Residents and Waitomo cave operators want DoC to stop Black Water Rafting conducting tours through Gardners Gut. The company has run them for at least 10 years without a licence.

Mr Scrimgeour said Black Water Rafting's educational tours were not illegal because they were not strictly commercial and were run at cost, but the department has now asked the company to apply for a licence.

He said Black Water Rafting was originally given permission to operate in Gardners Gut by the Tourist Hotel Corporation, which managed the reserve until 1990.

Waitomo Adventures managing director Nick Andreef said the cave should not be used for commercial caving and local cave operators were appalled that Black Water Rafting did not have to meet the same standards as other operators.

"Black Water Rafting has made a profit from using a public asset for free but has not been required to stipulate management plans or make any financial contributions to maintaining the cave or limiting the damage."

Black Water Rafting director Peter Chandler said the cave had been damaged by unmanaged recreational cavers who had uncontrolled access. Regular monitoring and a management plan for the entire system was needed to prevent further damage.

Black Water Rafting's application hearing was due to start last week but was postponed after the department bowed to pressure and agreed to hold a public meeting and allow further submissions.