Travellers have arrived at Hastings Country Park.
Hastings Borough Council – which owns the nature preserve – said it was working with Sussex Police and the county council to have the group moved on.
It is thought the group arrived on Saturday afternoon (April 20).
A council spokesman said: “Hastings Borough Council officers are working with the police and East Sussex County Council’s traveller liaison team to have the travellers moved on.”
East Sussex County Council has been approached for comment.