Liberal MP accuses Scott Morrison of ‘ruthless bullying’ and scheming at the expense of flood victims

Another senior Liberal has taken aim at Scott Morrison, accusing him of "self-serving ruthless bullying" and claiming he has "ruined" the Liberal party.

Catherine Cusack, a NSW Liberal who announced two weeks ago she would resign from the Legislative Council over her anger about flood relief, adds her voice to a growing chorus of critics of Morrison from within his own party in an opinion piece for Guardian Australia.

Cusack explicitly endorses Liberal senator Concetta Fierravanti-Wells's "character assessment of the prime minister" and reveals she will not vote for the Morrison government in the May election.

The prime minister's office was contacted for comment regarding Cusack's claims.

On Tuesday Fierravanti-Wells labelled the prime minister an "autocrat" and a "bully" in an excoriating Senate speech revealing allegations Morrison had made "racial comments" when running for preselection in 2007.

Morrison has vehemently denied the claims, contained in statutory declarations reported in the Saturday Paper and then publicly backed by his preselection opponent, Michael Towke.

Cusack accused Morrison of having "ruined" the Liberal party and "trashed" its values over two decades, as state director, "then as a scheming MP and now as prime minister finding loopholes in our constitution to delay preselections in order to get his way".