The Liberal staff member who was accused of stealing documents from his former employer - and now political rival -- has resigned.

Yan Plante said the allegations against him are false, and that he will spend "all his energy defending his reputation."

Plante was hired in August to work in the premier's office, after having spent eight months as a political advisor for Francois Legault.

At the time Plante told the CAQ that he had ideological differences with the direction the second opposition party was taking.

However this week, the Coalition Avenir Quebec said that Plante stole documents from the CAQ.

On Tuesday the CAQ sent lawyer's letters to Plante, and to the chief of staff of the Liberal Party, outlining the alleged wrongdoing.

The CAQ said that in the weeks and months before he left the CAQ, Plante emailed copies of the party's election strategy, as well as documentation on the CAQ's internal structure.

Simon Jolin-Barrette said that was a breach of confidentiality toward Plante's then-employer, the CAQ.

"Yesterday, all day, he made statements that what we were saying was not true. We have big questions about the judgment of Mr. Couillard and his chief of staff," said Jolin-Barrette.

He added that the CAQ is calling for Couillard's chief of staff, Jean-Louis Dufresne, to step down.

So far the CAQ has had two conversations with provincial police about the incident, and will meet with officers again a third time.

In a written statement, Plante said he has answered the CAQ's demands with a reply from his lawyer.

Plante only began working for the CAQ in November 2015, after working for federal Conservative Minister Denis Lebel.