The woman who lodged confidential sexual harassment allegations against Barnaby Joyce has blasted the Nationals for bungling the complaint, claiming the issue has been used for "political advantage" in a way that threatens to stop other women coming forward.

Fairfax Media on Wednesday revealed an internal review found the bombshell complaint - which forced the former deputy prime minister's resignation from cabinet on February 22 - was compromised by political interference, leading to the complainant's identity being exposed and denying the former deputy prime minister a fair hearing.

Catherine Marriott wanted the complaint to remain confidential but her name was leaked to the media.

The secret review by WA Nationals state president James Hayward questioned the conduct of state MPs who had "regular" communication with Catherine Marriott, the woman who lodged the complaint about Mr Joyce's behaviour outside an event at Canberra's Kurrajong Hotel in 2016.

The complaint was lodged with the Nationals at the height of the controversy over Mr Joyce's affair with a former staffer, and was promptly leaked to the media, along with Ms Marriott's identity.