Three leading board members of the Loch Lomond and Trossachs National Park authority have been reported to the ethical standards watchdog for allegedly failing to declare an interest in a fiercely disputed camping ban.

They all have homes in a proposed "management zone" to control camping but, according to observers, didn't make that clear at a board meeting that approved the plan. The minutes of the meeting in April were then written to suggest that they had declared that interest, critics say.

The park, however, dismissed the allegations as "utter nonsense", saying that declarations of potential interest had been made "entirely appropriately and clearly". The minutes were "not verbatim" and included information already available on the park's online register of interests, it said.

The mountaineering campaigner, Nick Kempe, has submitted a complaint to the Commissioner for Ethical Standards in Public Life in Scotland, Bill Thomson, about the conduct of the park's convenor, Linda McKay, and two other board members, Owen McKee and Martin Earl, at a board meeting on April 27 2015.

At the meeting they said that they owned residential properties in the park. But, according to Kempe, they did not specify that their houses were in the Trossachs North camping management zone.

This is one of the park's proposed zones in which by-laws will be introduced to ban camping without permission. The board meeting unanimously decided to approve the zones, which are now being considered by the Scottish Government.

The zones, which cover long stretches of the park's loch shores, are aimed at combatting littering and anti-social behaviour by summertime campers from urban areas. But they have been strongly opposed by outdoor campaigners who say they undermine Scotland's 'right to roam' law and will criminalise hundreds of innocent campers.

After the April meeting, Kempe wrote to the park authority asking which board members had properties in camping management zones. In a reply on May 27, he was told that McKay, McKee and Earl had homes in the Trossachs North zone.

When the minutes of the April meeting were posted online in June, they recorded the three board members as saying that they owned properties in the zone. But Kempe insists that they had not said this, and called on them to resign.

"The leadership of the national park appears prepared to do anything to promote their own agenda," he said. "The government now needs to instigate a full scale investigation."

Kempe was president of the Mountaineering Council of Scotland and a former board member of the government agency, Scottish Natural Heritage. His account was backed by Peter Jack, chairman of the Loch Lomond Association, which represents water users.

"The minute has been blatantly manipulated to misrepresent what happened at the board meeting," Jack said. "It's a disgrace, and merits an official external independent inquiry."

Dave Morris, former director of Ramblers Scotland, compared the park board to a residents' association. "Their first priority is in protecting their own property values, ensuring that nobody is camping within sight or sound of their own loch shore houses," he said.

The allegations, however, were dismissed as "somewhat hysterical" by the park's chief executive, Gordon Watson. "These accusations are utter nonsense," he told the Sunday Herald.

"Mr Kempe is desperately trying to find shadows where none exist; seeking to derail by any means much-needed and carefully considered proposals. To be 100 per cent clear, our board members have fully observed all procedures in relation to declarations of interest. The fact that some of them live within the proposed zones is a matter of repeated public record."

Declarations of potential interest had been made "entirely appropriately and clearly" at the April board meeting, Watson said. "The draft minutes available online, which are not verbatim, highlighted the declarations and included relevant information already available in the register of interests."

The public register of interests included address details of board members, he added. The fact that some were in a camping management zone had been declared at a previous board meeting on the subject on October 6 2014.