(2) Subject to the control of the Director-General, a Deputy Director-General shall have and may exercise all of the powers, duties, and functions of the Director-General (including any powers delegated by the Minister under section 57) and shall perform any other duties the Director-General thinks fit.
(3) On the occurrence from any cause of a vacancy in the office of Director-General (whether by reason of death or resignation, or otherwise), or in the case of absence (from whatever cause arising) of the Director-General, and for so long as the vacancy or absence continues,—
(b) a Deputy Director-General authorised in writing in that behalf by the State Services Commission (before, on, or after the occurrence of the vacancy or absence) in every other case,—
shall have and may exercise and perform all the powers, functions, and duties of the Director-General (including any powers delegated by the Minister under section 57).
(4) The fact that a Deputy Director-General exercises or performs any power, function, or duty of the Director-General shall be conclusive evidence of the authority of the Deputy Director-General to do so; and no authority given under subsection (3)(b) and no act done by a Deputy Director-General under any such authority or under subsection (2) or subsection (3) shall in any proceedings be questioned on the ground that the occasion for the giving of the authority had not arisen or had ceased or that the act was contrary to a direction of the Director-General.