The future of a popular Gwynedd campsite is in doubt because access for emergency services cannot be guaranteed, its owners have said.
Emergency vehicles have reached Shell Island - which is regularly cut off by high tides - via the neighbouring Llanbedr Airfield for decades.
Campsite director Richard Workman said changes made by the airfield's tenant, Snowdonia Aerospace LLP, are "unfair".
Snowdonia Aerospace said access was still possible.
The main route to Shell Island - one of the biggest campsites in Europe - is via a causeway which is cut off by the tide twice a day, every other week.
Mr Workman said that Snowdonia Aerospace initially proposed to stop any kind of emergency vehicle access across the Welsh Government-owned airfield by the end of March.
Now they have negotiated a temporary arrangement where emergency services will have to call a mobile number issued by Snowdonia Aerospace.
The gate will then be opened and the vehicle escorted over the airfield - but only if someone is available to do so.
'Urgently seeking clarity'
Mr Workman said he fears the firm could renew its bid to completely withdraw access.
"We don't believe anyone has a right to stop emergency services from reaching people in need and are urgently seeking to clarify the legality of their decision to block what has been an agreed access route for many decades," he said.
"Our beautiful coastal site has been a much-loved holiday destination for generations of visitors and it provides significant employment for many families in our local community.
"Gwynedd council and the emergency services say they are satisfied that the campsite can stay open in the short term, but all visitors must be made aware of the current emergency services situation so that they can make their own decision about risk."
Snowdonia Aerospace partner David Young said: "In the event of emergency access being required, the request simply has to be made to our duty staff member on a mobile telephone.
"The directors of Shell Island have been invited to have talks with us about their emergency access problem but they have declined to do so."
A Welsh Government spokesman "We are pleased that a short term solution has been agreed. However, we encourage both parties to explore all options available as a longer term solution is necessary if the site is to maximise its potential."