Haw. Rev. Stat. § 657-20: Extension by fraudulent concealment.

If any person who is liable to any of the actions mentioned in this part or section 663-3, fraudulently conceals the existence of the cause of action or the identity of any person who is liable for the claim from the knowledge of the person entitled to bring the action, the action may be commenced at any time within six years after the person who is entitled to bring the same discovers or should have discovered, the existence of the cause of action or the identity of the person who is liable for the claim, although the action would otherwise be barred by the period of limitations.