Plans for a buffer zone to ease the problems caused by lorry tailbacks from the Port of Dover in Kent have come up against "considerable hurdles".
Ferry disruption at Dover's Eastern Docks can cause traffic chaos
Dover Harbour Board wants to build a site for up to 1,500 trucks on greenbelt land to the west of the town.
Its aim is to bring an end to Operation Stack, where heavy goods vehicles are parked on the M20 during disruption at the port's ferry terminal.
But the harbour board has admitted it faces serious planning restrictions.
The site being proposed is believed to be at Court Wood, in an area of outstanding natural beauty between Farthingloe and Aycliff.
Dover Harbour Board announced the plans last November, but chief executive Bob Goldfield said on Tuesday: "The hurdles about the buffer zone are considerable and we're not sure yet that we can actually overcome them."
Operation Stack is implemented when large numbers of heavy goods vehicles begin queuing to get into Dover, often because of adverse weather conditions or delays to ferry services.
The harbour board is also planning to address capacity problems with a new ferry terminal at Dover's Western Docks.
Mr Goldfield said that would absolutely have to go ahead even if the buffer zone plans fell through.
The terminal at the Western Docks has been out of use since Hoverspeed pulled out, and the plan is to completely renovate it so the berths can accommodate the same size ferries as the Eastern Docks.