Haw. Code R. § 12-43-43
Pursuant to chapter 89 or 377, HRS, the board may at any time institute investigations on its own initiative into any matter governed by chapter 89 or 377, HRS. The board shall serve its notice of investigation upon the employee, public employee, employee organization, employer, or public employer being investigated or having a direct interest or concern in the matter under investigation and shall designate the time and place for the investigation. In conducting an investigation or inquiry, the board may request or subpoena information from an employee, employee organization, or employer that is subject to chapter 89 or 377, HRS, or question a party, witness, a party's attorney, or other representative appearing before the board, with respect to any matter.
Haw. Code R. § 12-43-43