Federal MP Don Randall says he has wide support within the state Liberal Party for his attack on the state's police minister Rob Johnson and his call for him to be dumped.
In federal parliament on Thursday the member for the seat of Canning accused his fellow Liberal of being a bumbling embarrassment to the party and failing to do his job.
Mr Randall said he had no confidence in Mr Johnson and his "silly and incompetent behaviour" as police minister and as former emergency services minister.
He said that after the devastating Perth Hills bushfire in February 2011, Mr Johnson had blamed everyone else but refused to take any responsibility himself.
In response, Mr Johnson said he had never been subjected to such a vitriolic and personal attack in his 20 years in parliament and Mr Randall's comments, made under parliamentary privilege, were abusive and defamatory.
On Friday Mr Randall told ABC Radio that his attack on Mr Johnson was done reluctantly and out of frustration at the minister's lack of assistance in addressing law and order and other issues in his Canning electorate.
Mr Randall said he had warned Mr Johnson's office for some time he would take such action.
"There's nothing personal other than the fact I wanted the minister to do his job," he said.
Mr Randall said said he would welcome any party disciplinary hearing over his speaking out because that would give him the opportunity to justify his actions.
"Do I have any support in the state parliamentary party? You bet I do and I can tell you it comes from cabinet ministers down to backbenchers," he said.
"We need vital people to do their job, not time-servers."
Premier Colin Barnett said in a brief statement from Singapore on Thursday that "minister Johnson has my full confidence and support".
