At this point is is best to stop peeling the paint, sand down the edges if possible, prime and repaint the affected areas.
The main thing is to figure out what is causing the lack of adhesion. Is the peeling happening on the areas that were repaired? Is the paint peeling only or is this down to the original surface? If the paint and primer is peeling then the problem could be with the primer or the newly repaired plaster. Plaster has a high PH and normally is primed after 3-4 weeks, this allows for a full cure of the plaster. There are primers that can deal with the high PH of new plaster.
Was a real plaster used or drywall mud? How old is the paint? How did the peeling happen or start?