They moved there after thousands of people crossed the harbour bridge on foot yesterday, in a march organised by the Freedoms and Rights Coalition
Camping is not permitted in the Domain, which lies between the suburbs of Parnell and Grafton.
Auckland Council director of customer and community services Claudia Wyss said it was working with event organisers on a safety-first approach.
She said there was no timeline for reopening at this stage and the council apologises for any inconvenience.