Haw. Rev. Stat. § 398-8: Prohibited acts.

(a) It shall be unlawful for any employer to interfere with, restrain, or deny the exercise of or the attempt to exercise, any right provided under this chapter.

(b) It shall be unlawful for any employer to discharge or in any other manner discriminate against any individual for opposing any practice made unlawful by this chapter.

(c) It shall be unlawful for any person to discharge or in any other manner discriminate against any individual because the individual has:

(1) Filed any charge, or instituted or caused to be instituted any proceeding, under or related to this chapter;

(2) Given or is about to give any information in connection with any inquiry or proceeding relating to any right provided under this chapter; or

(3) Testified or is about to testify in any inquiry or proceeding relating to any right provided under this chapter.