TORONTO -- Ontario's premier took another step toward a defamation lawsuit against the province's Opposition leader Friday after he refused to retract comments suggesting she is personally on trial.

Kathleen Wynne's lawyer demanded in a letter last month that Progressive Conservative Leader Patrick Brown withdraw comments he made a day before the premier testified as a witness at a trial in Sudbury, Ont., involving two provincial Liberals facing Election Act bribery charges.

Brown had told reporters he hoped Wynne would give answers about the scandal "maybe when she stands trial" and went on to describe her as a "sitting premier, sitting in trial."

After receiving the lawyer's letter, Brown said he would "ignore her baseless legal threat." When asked to explain why, he said it was a "sad day for Ontario" to see the premier "debased" and "humiliated" by testifying in court.

Wynne's lawyers followed up Friday with another letter to Brown saying it constitutes a notice of libel.

Brown's comments about the premier being debased and humiliated are another defamation, her lawyers wrote.

"Our letter of September 13, 2017 was intended to provide you with an opportunity to partially mitigate the damage you have done with a retraction, an apology, and an undertaking to refrain from making any further defamatory statements about Premier Wynne," Jack Siegel and Sheldon Inkol wrote.

"Not only did you refuse to make a retraction or to apologize, you chose to compound the problem by making further defamatory statements. Accordingly, a legal action will now be commenced against you for defamation."

Brown repeated the comments about the premier being debased and humiliated Friday in a statement responding to the libel notice.

He suggested the notice was a way for the premier to distract the public from another ongoing trial involving two staffers of former Liberal premier Dalton McGuinty, and a critical auditor general report earlier this week on the Liberal government's plan to cut hydro bills.

"Make no mistake, it is political corruption that's on trial," Brown wrote. "And the premier is oblivious to the fact that her party is politically corrupt."

Brown suggested Wynne should be the one to apologize, for "years of waste mismanagement and political corruption in this province."

"We as a province need to put this ugly chapter behind us and move on," Brown wrote.

Wynne's lawyers said Brown's status as leader of the Progressive Conservatives increased the likelihood that his statements would be repeated by others, therefore "increasing the potential harm to the premier's reputation."

The "stubborn refusal" to retract the comments has put Brown on the hook for potential aggravated and punitive damages, they wrote in the libel notice.

The lawyers also warned Brown that he must preserve all relevant documents, because if Wynne proceeds with a lawsuit he will be required to disclose them all.

Speaking in Windsor, Ont., after meeting with two U.S. governors on Friday, Wynne was vague about her hopes for what would come from the libel notice.

"An acceptable outcome for me is to have a debate about the truth, whatever the subject we're talking about, to talk about the facts and talk about the substance of the issues," she said. "That's to me the best outcome in any political situation."

Progressive Conservative Bill Walker apologized last month after receiving a letter from Wynne's lawyer for remarks he made suggesting the premier was under investigation and facing charges in connection with the Sudbury bribery trial.

Wynne previously sued former Progressive Conservative leader Tim Hudak and another Tory member of provincial parliament after the pair said she oversaw -- and possibly ordered -- the destruction of documents related to two cancelled gas plants. Those are the allegations for which the two McGuinty-era staffers are currently on trial.

That lawsuit was resolved in 2015, though it is not known whether it was settled or withdrawn.