The travellers had set up in Adur Park, just off Lion Hill, on Friday, May 7 before an order was issued by the authorities.
They left on Sunday May 9.
A spokesperson from Wealden District Council said, “On Monday May 11 Wealden District Council was contacted by local residents who had been litter picking after the park had been vacated.
“Bags of litter were left collected together and these have now been removed by our street cleansing contractor, Biffa.
“We have also been informed by Westham Parish Council of some reports of human waste being left in the undergrowth at the park.
“Wealden street scene officers are investigating this matter and we will be working with the Parish Council as the owner of the park to help them clean up.”
Local resident Jenny Wallace-Elliot, who joined others in helping collect some of the rubbish, said, “I think it is disgusting.
“The council should do more and make places more secure.
“The residents have done a remarkable job.”
Westham Parish Council clerk Susan Sanders added, “On behalf of Westham Parish Council I would like to thank East Sussex County Council,
“Wealden District Council and the police for helping to resolve the situation in Adur Park very quickly.
“Also, we would like to thank the volunteers who were out first thing on Monday morning litter picking the area. However, we are waiting for Wealden DC officers to inspect the site and let us know their views before we can completely clear the site especially in regard to the long grass and wooded areas.”
In regards to making the park more secure the Parish Council clerk said, “At the moment as you are probably aware we are still in the process of clearing the site and we are unsure as to how long this will take because bags have been thrown into trees and bushes.
“This means that we have to allow access for council vehicles to clean up the site.
“We are at the moment considering a number of options to prevent a recurrence of what happened last week but we have to carefully consider the right balance.
“On the one hand the public quite rightly want free access to Adur Park but on the other hand we have to prevent any recurrence of the damage to the park.
“Obviously it is totally impossible to secure the park and let the public have access at the same time.”