Veteran Liberal MP Charlie Lynn has launched an extraordinary attack on NSW cabinet minister Jai Rowell, accusing him of using his influence to dissuade three women from seeking upper-house preselection to secure a spot for his ally, Wollondilly councillor Lou Amato.

In a letter to NSW Liberal president Chris Downy, Mr Lynn blasts the outcome as "factional misogyny" and demands the party disendorse Cr Amato and install his colleague Dai Le instead.

NSW Mental Health Minister Jai Rowell. Credit:Jeff de Pasquale

Mr Lynn, the parliamentary secretary for veterans affairs, says he understands Mr Rowell, the Minister for Mental Health and a leader of the right faction, met three women including Ms Le and "persuaded them to withdraw from the process".

He also claims Mr Rowell even persuaded Ms Le to sign Mr Amato's nomination form, despite never having met him.