"In accordance with the rules of the Hawaii Republican Party, our party has terminated the membership of Ms. Kaaihue based on her public statements on social media that she is 'not a Republican,'" said party Chairman Fritz Rohlfing.
"Additionally, Ms. Kaaihue has filed as a Democrat in the upcoming special election for the remainder of the term of the late U.S. Rep. Mark Takai in Congressional District 1.
Kaaihue, who was previously running against incumbent U.S. Rep. Tulsi Gabbard, announced over the weekend she would be running as a Democrat in the special election.
Meanwhile, Hawaii's Democratic Party said it would file a complaint with the First Circuit Court because Kaaihue is not a registered Democrat.
In response, Kaaihue issued a statement inviting the legal challenge.
"I'm not in violation of any policies," she said. "As far as I'm concerned, changing parties is construed as a positive thing."