23. Procedure for and restrictions on rectification of mistakes

Any authority under the Act may, of his own motion or on an application being made in this behalf, rectify any mistake apparent on the face of the record in any order passed by such authority including its predecessor-in-office and any authority subordinate to it: 

Provided that if an order under this rule has an adverse effect on an employer or a person, no such order shall be passed unless a reasonable opportunity of being heard has been given to such employer or person: 

Provided further that no order under this rule shall be passed after the expiry of three years from the passing of the impugned order.