Hawaii Revised Statutes Division 1. Government § 231-15

Every return statement, or other document required to be made for taxation purposes shall be signed in accordance with forms or regulations prescribed by the department of taxation. Where forms or regulations have not been prescribed, every such return, statement, or other document shall be signed by the person required to make the return, statement, or other document or by some duly authorized person in the person's behalf.

The department of taxation may require that, if any person or persons actually prepare or sign a return for another person, the person or persons so preparing or signing the return shall sign a statement showing such facts and such authority to sign such return as may be prescribed by the department, and the department may by regulation define the classes of persons to whom this provision shall apply.

Any other provision of law to the contrary notwithstanding, no oath shall be required upon any tax return.