Wherever, by the provisions of any law of the State, any act is required to be performed by the chief justice of the supreme court, the act may (unless otherwise expressly provided) be performed, in case of a vacancy in the office of chief justice, or if the chief justice is ill, absent, or otherwise unable to serve, by an associate justice of the court designated in accordance with the rules of the supreme court.
HRS § 602-3
See Const. Art. VI, §2.