Haw. Rev. Stat. § 806-50: Standing mute.

If any person being arraigned upon or charged with any offense, stands mute of malice, or will not answer directly to the indictment, the court (if it shall so think fit) may order the proper officer to enter a plea of "not guilty" on behalf of that person, and the plea so entered shall have the same force and effect as if the person had actually pleaded the same.