Haw. Rev. Stat. § 804-15: Recognizance.

In all cases where a magistrate either commits for trial or bail the accused, the magistrate may cause each of the witnesses who has been examined and has testified to any material fact or circumstance in the case to enter into a recognizance, with or without surety, at the magistrate's discretion, in a sum fixed by the magistrate, conditioned for the witness' appearance at the sitting of the court at which the accused is bound or committed to appear. If a witness refuses to sign the recognizance when required, the witness may be committed to jail by the order of the magistrate, and shall be confined until the witness is brought before the court to testify, or until the witness gives the recognizance.