Notwithstanding anything to the contrary contained in any law or rule for the time being in force, no representation shall lie against any order passed under the provisions of this Part on the expiry of three months from the date of publication or service, whichever is earlier, of such order:
     Provided that the Central Government may, suo motu or otherwise and for reasons to be recorded, reopen any matter and pass such orders thereon as may appear to it to be appropriate if it is satisfied that it is necessary so to do in order to prevent any miscarriage of justice to any affected person.