The camp was set up by the 1968 Foundation in support of Gus Hales, who has led a campaign to raise awareness of veterans' issues and spent two weeks on hunger strike on the Shuker Field near the Combat Stress centre on Audley Avenue.
The volunteers supported Gus and other veterans who visited.
But there was a falling out between Gus's team and the 1968 Foundation, and the groups continued their campaigning separately.
Last week the 1968 Foundation withdrew its camp from Newport after seeing Combat Stress "step up" its care for veterans.
And Gus's supporter Tyrone Allday said the state they left their camp in was an "absolute disgrace", with bin bags full of material, loose pallets and a large tent remaining on the field.
Tyrone took to social media to say: "I hope you are happy with the state you have left the field in. You have taken so much from the people of Newport and this is how you thank them, by leaving all this rubbish, clothes, quilts, wood, who knows what else.
"Shows how much you have taken advantage of the generosity and kindness of the Newport community."
But Steve Wood of the 1968 Foundation said the group removed everything it had responsibility for, and that much of the things left on the site had been donated to Gus.
"Some of the members of Gus's camp made it very obvious to me that those items were not donated to me or the 1968 Foundation, and that I was to leave them alone.
"I was told in no uncertain terms that I was not to touch those items. That was fine by me.
"Everything that was associated with the 1968 Foundation such as refuse was removed by me.
"I am not shirking my responsibility."
The remainder of the camp has since been cleared away by Newport residents.