Lincolnshire County Council has taken steps to tackle illegal overnight camping in its Marsh Yard car park near Anderby.
The move comes after a number of complaints from the community.
And a senior council figure has warned that the authority will “continue to take similar action” to prevent repeat incidents.
The council does not permit overnight camping in any of its six coastal car parks.
Working alongside Lincolnshire Police, officers from the council have now locked the height barrier at the entrance to the site.
Those who have yet to leave will need to contact the council to arrange for the barrier to be temporarily unlocked again.
Coun Colin Davie, executive member for the environment, said: “We have taken this step in order to prevent people from camping overnight in our car park.
“We have been speaking with the people who have been staying on the site to make them aware of our plans. They have been given plenty of notice to leave but this has been ignored.
“Closing the barrier will prevent further instances like this occurring, and encourage the remaining individuals to leave.
“I appreciate many people want to use this area and enjoy the spectacular views of the coastline, but this situation was unacceptable and I felt Lincolnshire County Council had to take decisive action.
“We will continue to take similar action at our other sites across the county, as and when required,” he added.