Haw. Rev. Stat. § 245-12
The director of taxation, and any agent of the director duly authorized by the director to conduct any inquiry, investigation, or hearing hereunder, shall have power to administer oaths and take testimony under oath relative to the matter of inquiry or investigation. At any hearing ordered by the director, the director or the director's agent authorized to conduct the hearing may subpoena witnesses and require the production of books, papers, and documents pertinent to the inquiry. No witness under subpoena authorized to be issued by this section shall be excused from testifying or from producing books or papers on the ground that such testimony or the production of such books or other documentary evidence would tend to incriminate the witness, or subject the witness to penalty or forfeiture; but no person shall be prosecuted, punished, or subjected to any penalty or forfeiture for or on account of any act, transaction, matter, or thing concerning which the person shall, under oath, have testified or produced documentary evidence.
Contempts. If any person disobeys such process or, having appeared in obedience thereto, refuses to answer any pertinent question put to the person by the director or the director's authorized agent, or to produce any books and papers pursuant thereto, the director or such agent may apply to the circuit court of the circuit wherein the taxpayer resides or wherein the transaction, act, or activity under investigation has occurred, or to any judge of such court, setting forth such disobedience to process or refusal to answer, and the court or the judge shall cite such person to appear before the court or the judge to answer such question or to produce such books and papers and, upon the person's refusal so to do, shall commit such person to jail until the person shall testify, but not for a longer period than sixty days. Notwithstanding the serving of the term of such commitment by any person, the director may proceed in all respects with such inquiry and examination as if the witness had not previously been called upon to testify.
Fees. Officers who serve subpoenas issued by the director or under the director's authority, and witnesses attending hearings conducted by the director hereunder, shall receive like fees and compensation as officers and witnesses in the circuit courts of the State, to be paid on vouchers of the director, from any moneys available for litigation expenses of the department of taxation.
HRS § 245-12