For nearly four decades, the future of the city’s central waterfront has been fiercely debated. The latest volley, fired by a lawyer representing the Committee for an Open Waterfront, accuses the Newburyport Redevelopment Authority of holding clandestine conversations concerning its plans to develop its 4.2-acre parcel on the ­Merrimack River.

Mark Peters, a Boston attorney, is threatening to take the issue to state officials. The authority, he contends, has committed “evident violations of the Open Meeting Law.”