79. Review of policy statements and plans---(1) Every regional council
 shall commence a full review of its regional policy statement, and each
 of its regional plans, not later than 10 years after the statement or
 plan became operative.

   (2) Every territorial authority shall commence a full review of its
 district plan not later than 10 years after the plan became operative.

   (3) If, after reviewing a policy statement or plan under this section,
 a regional council or territorial authority considers---
   (a) That the statement or plan requires change or replacement, it
         shall change or replace the statement or plan in the manner set
         out in the First Schedule and this Part:
   (b) That the statement or plan can remain without change or
         replacement, it shall publicly notify that statement or plan as
         if it were a proposed policy statement or plan in the manner set
         out in the First Schedule and this Part.

   (4) When a regional council or territorial authority is reviewing a
 policy statement or plan, it shall review all sections of, and all
 changes to, the policy statement or plan regardless of when those
 sections or changes became operative.

   (5) A policy statement or plan shall not cease to be operative by
 virtue of being due for review or while it is being reviewed.

   (6) The obligations of each regional council and territorial authority
 under this section are in addition to its duty to monitor under section
 35.