Haw. Rev. Stat. § 231-57: Apportionment of joint refunds.

In the case of a setoff against a joint income tax refund, the State may make separate refunds of withheld taxes upon request by a husband or wife who has filed the joint return. The refund payable to each spouse shall be proportioned to the gross earnings of each shown by the information returns filed by the employer or otherwise shown to the satisfaction of the State.