Haw. Rev. Stat. § 571-24
Any person summoned as provided in section 571-23 who, without reasonable cause, fails to appear, may be proceeded against for contempt of court. If the summons cannot be served, or if the parties served fail to obey the summons, or if it is made to appear to the judge that serving the summons will be ineffectual or that the welfare of the minor requires that the minor be brought forthwith into the custody of the court, a warrant may be issued for the parent, the guardian, or the minor.
If, after being summoned or notified to appear, a parent fails to do so, a warrant may be issued for the parent's appearance, and the hearing shall not take place without the presence of one or both of the parents or the guardian, or, if none is present, a guardian ad litem appointed by the court to protect the interests of the minor. The court may also appoint a guardian ad litem, whenever this is necessary for the welfare of the minor, whether or not a parent or guardian is present.
HRS § 571-24
Rules of Court
Guardians ad litem, see HFCR rule 17(c).