The Garda Commissioner Nóirín O'Sullivan has reiterated her assertion she has done nothing wrong in relation to Maurice McCabe.

In a statement Monday, Commissioner O'Sullivan said: "My position remains unchanged. Nothing has emerged in the last three weeks which in any way changes that situation.

"A campaign of false accusations, repeated and multiplied, do not make me guilty of anything.

"I have made it clear that I was not part of any campaign to spread rumours about Sergeant McCabe and didn't know it was happening at the time it was happening. I have repeatedly refuted that claim and do so again.

"The easiest option for me would be to step aside until the commission finishes its work.

"I'm not taking that option because I am innocent and because An Garda Síochána, under my leadership, has been making significant progress, with the help of our people, the Government, the Policing Authority and Garda Inspectorate, in becoming a beacon of 21st century policing."

A Commission of Investigation to be chaired by Mr Justice Peter Charleton is to examine the allegations.

Earlier, Fianna Fáil's justice spokesman Jim O'Callaghan told Newstalk Breakfast he is '100% certain' he told Tánaiste Frances Fitzgerald last Wednesday about false Tusla allegations against Mr McCabe.

Speaking this afternoon, Deputy O'Callaghan said the Government will collapse if the process of setting up a Commission of Investigation is not sorted out. 

However, he added that a collapse of the Dáil at the moment would mean "we won't have any Commission of Investigation - that serves the interest of nobody". 

Ms Fitzgerald has insisted she only learned about the Tusla allegations in media reports on Thursday.

In a statement Sunday, Ms Fitzgerald said: "Deputy O'Callaghan spoke to me about the terms of reference the day before the Dáil debate (Wednesday).

"He suggested the terms of reference should be broadened to bring absolute clarity that the allegation of criminal misconduct against Sergeant McCabe and the alleged smear campaign would be investigated.

"Deputy O'Callaghan said to me that PrimeTime would have a programme the following evening related the establishment of the Commission.

"At no point did he mention Tusla or any of the details that emerged in the programme," she added.

Last week, Sinn Féin deputy leader Mary Lou McDonald called on Commissioner O'Sullivan "to step aside with immediate effect" after revelations that false allegations against Mr McCabe were put into a Tusla document.

Ms McDonald said the revelations were "quite frankly disgusting and vile."

"Such are the allegations in this case, it is in incumbent on the Garda Commissioner Nóirín O'Sullivan to step aside immediately for the duration of the Charleton Commission's investigation," she added.

It comes as the Government faces a no confidence motion put forward by Sinn Féin.

The party is seeking support from Fianna Fáil and from opposition TDs for the vote, which will be held in the Dáil this week.