(5) Where an invitation to commence collective bargaining has been made and a reply notifying acceptance has been given the parties shall commence collective bargaining within thirty days from the date of receipt of the reply notifying acceptance of the invitation.
(6) Where an invitation to commence collective bargaining has been made and the invitation has been refused or not been accepted within fourteen days, or where no collective bargaining has commenced within thirty days from the date of receipt of the reply notifying acceptance of such invitation, the party making the invitation may notify the Director General in writing, whereupon the Director General may take such steps as may be necessary or expedient with a view to bringing the parties to commence collective bargaining without undue delay.