After preparing the comprehensive plan, or successive parts thereof, as the case may be, the planning agency shall hold at least one public hearing on the comprehensive plan or successive part. Notice of the time, place, and purpose of such public hearing shall be given as provided by ordinance and including at least one publication in a newspaper of general circulation delivered in the code city and in the official gazette, if any, of the code city, at least ten days prior to the date of the hearing. Continued hearings may be held at the discretion of the planning agency but no additional notices need be published.