Applications to intervene in a proceeding shall comply with section 19-1-10 and shall be served upon all parties. Applications for intervention will be granted to persons properly seeking and entitled as of right, to be admitted as a party; otherwise at the discretion of the presiding officer, they may be denied. As a general policy, such applications shall be denied unless the petitioner shows that it has an interest in a question of law or fact involved in the contested matter.
Haw. Code R. § 19-1-20