Two tents have been erected in the last few weeks and, at one time, four people were camping there.
After the first one went up, Dublin City Council directed its occupier, Michael Connors, and businessman Noel O'Gara to have it removed.
However, another tent appeared in the meantime.
Now, Labour's Oisin Quinn wants the council to seek a High Court injunction directing a removal.
Mr Quinn said, at one stage, at least four people were sleeping in the tents.
The controversy is the latest to hit Dartmouth Square since Mr O'Gara bought the park for less than €10,000 three years ago.
In June last year, a court ordered that the assets of Mr O'Gara be seized unless he complied with a court order not to make unauthorised use of the square.
He was before the Circuit Civil Court on foot of an application by the council to have him jailed for breaching a previous court order. Mr O'Gara had been ordered to remove a caravan and generator,.
Cllr Quinn said today: "I've told the manager they [the council] should go to court looking for an injunction because of the history attached to it."
The injunction should direct Mr O'Gara to remove the tents, he added.
He said the problem stems from the failure of the council to complete a compulsory purchase order for the park.
"It means that the residents are continuing to endure these kinds of frustrations. The problem still has to be resolved. It is incumbent on the city manager and the council to work with residents. In my view, it's the city manager's responsibility to take every legal step available."
A spokesman for the council told the Herald an enforcement notice was issued on October 28 in respect of two tents in Dartmouth Square.
The notice required that they be removed and no further tents be erected in the future.
It was to be complied with by November 3 but a council inspection the following day revealed this had not happened, the spokesman said.
He said the council has now issued legal proceedings in the district court in respect of the non-compliance.