WA Corrective Services Minister Joe Francis has defended comments about a senior public servant that sparked a defamation action, claiming he made the criticisms on advice provided by his department.

Taxpayers will foot the undisclosed legal costs of a confidential defamation settlement involving Mr Francis and former Department of Corrective Services (DCS) chief financial officer George Kessaris.

In March, Mr Francis publicly blasted Mr Kessaris, saying he had been "caught out for incompetence".

The attack came after an internal memo Mr Kessaris wrote revealing significant "governance concerns" was leaked to the media.

The ABC understands the DCS does not know who leaked the memo and Mr Kessaris denies it was him.

On Monday the ABC revealed Mr Kessaris sued Mr Francis for defamation and the case was settled out of court, including the letter of apology and a confidential financial payout.

George Kessaris sued Joe Francis for defamation and the case was settled out of court. ( ABC News: Laura Gartry )

Speaking for the first time publicly, Mr Francis blamed the DCS for providing "incorrect" advice.

"Now if I wasn't the Minister for Corrective Services I wouldn't have been doing a press conference about DCS' finances on Easter Saturday," he said.

"I did that on the best knowledge and advice that I had at the time from the department at the time and I made those comments accordingly."

Mr Francis told journalists that media conferences were also to blame.

"I've already tried to be open and direct with the media when you ask me questions, now if you want me to stop and get legal advice every time single time I go and I do that, press conferences like this just would not happen," he said.

"So it's about a balance."

Mr Francis said that he did not name Mr Kessaris, instead using his job title, and that Mr Kessaris had accepted his written apology.

Mr Francis said there was a longstanding policy in place to indemnify ministers from legal costs.

"Where the conduct of ministers and public officials was in good faith and reasonable, and in the discharge of official responsibilities, the state will meet legal costs," he said.

Messenger shot: Opposition

State Opposition leader Mark McGowan said it was "outrageous" that taxpayers were paying the legal costs.

He said the Government was not following its own policy.

"It wasn't fair, reasonable or right that the taxpayers are paying for Mr Francis shooting his mouth off and attacking a public servant," he said.

"Already this senior public servant has gone on leave at enormous cost, there will have been enormous legal expenses and whatever the settlement is, is being borne by the taxpayer because Mr Francis couldn't control himself."

Mr McGowan said Mr Francis had been exposed for incompetence and had shot the messenger.

"If we are successful in the election next year, we will be revealing all these costs so the taxpayers can find out how much they are spending fixing up Mr Francis's mistakes," he said.