The Sinn Féin leader has said gangland violence is a scourge that has devastated decent, hard working communities and that a case that is currently before the Special Criminal Court is "concerning to us all".

Mary Lou McDonald said the case is "clearly an important one" but that she did not want to say anything that might jeopardise it.

"I know anybody who knows me and who knows my track record actually knows how I feel very strongly on these issues. Obviously I can't comment on specific individuals who are before the courts, but be in absolutely no doubt that my position is of zero tolerance."

Speaking on The Late Late Show on RTÉ One, the Sinn Féin leader described as "despicable" the inclusion of some details about her early family life, including what she described as trauma from her childhood, in a book written about her by former Independent Minister Shane Ross.

Ms McDonald said she was hurt and furious that Mr Ross had written about a time in her life that she said was "hugely traumatic" for her family and with the way it had been presented.

"I'm a public figure and that goes with the territory. But my family aren't and my family aren't up for grabs. And in the book, there is things written about my childhood, written about a time in our lives that was hugely traumatic for my family.

"And I think, to write that, to find the sore spot in someone's life, particularly trauma when you're a child, and you have no influence over it, and then to write that up almost like as a 'gotcha'. And to describe that, as it is in the book is like a skeleton in your closet, I think is wrong.

"I think it's kind of despicable. I was furious and I was hurt mainly for my mother. I mean, I am a public figure. If there's things to be said and analysed about me, that's fine. I happen to think that our families are not up for grabs."

Deputy McDonald also said the home she resides in is "far from a mansion".

She said the property in Cabra is her family home that she has a mortgage on and that she and her husband have "a little bit to go to pay back".

Mary Lou McDoanld admitted she found some aspects of the prospect of becoming Taoiseach in the future daunting.

She said she would be foolhardy not to feel a little bit of pressure but that she also felt a sense of purpose and excitement about the challenge of demonstrating how a woman could be Taoiseach and how a republican could be Taoiseach.

The Sinn Féin leader also said that she thinks the prospect of a Sinn Féin overall majority in the next election or for Sinn Féin and Fine Gael to share power would be a "long shot".

Mary Lou McDonald said the best outcome after the next election would be for a new government without Fianna Fáil and Fine Gael for the first time in over a century.

She said she would "move heaven and earth" to put together and lead a government of the left if the electorate feel it is a live and attractive option.

She also said she took responsibility for not running enough candidates in the 2020 election and that she was "sorry" about this and would not make the same mistake again.

Deputy McDonald said she thinks the 12th of July should be a public holiday in a United Ireland but that the current Republic of Ireland flag should be maintained.

She also said that Ireland is not unique in having a housing challenge but that "we seem to be uniquely incapable of getting to grips with it". The State and the Government need to solve the problem rather than the private market, she added.