Victims' feelings 'whipped up' claims Martin McGuinness
Martin McGuinness has said the focus on his IRA past was an attempt by the media to use the feelings of victims against him.
Sinn Fein confirmed on Sunday it was backing Mr McGuinness' bid to become head of state in the October poll.
"I think it's an attempt by the media to whip up the feelings of victims and try to use the feelings of victims," he said.
He added the IRA was one participant in "a very bitter conflict".
"The IRA was a participant and I was in the IRA - I don't divest my responsibility for that, I do believe that I have a responsibility given that I was a member of the IRA," Mr McGuinness said.
"I believe that the people of Ireland will look at my record in the round I think they will see me as a peacemaker, they will see me as someone who has tried to inspire people in the north in favour of the peace process."
He said he would not apologise for being in the IRA but there were things the IRA did "which were wrong and should not have happened".
The Sinn Fein deputy leader also said he would meet the Queen if elected, something which his party has refused to do in the past.
"I am going forward as Martin McGuinness in my own right, I'm not going forward as a representative of Sinn Fein," he said.
"My allegiance is to the people of Ireland.
"As part of my responsibility if I was lucky enough to be elected as president of my country would be to represent my country on the world stage and to meet with foreign dignitaries without exception."
Earlier, Ulster Unionist leader Tom Elliott said unionists would feel more comfortable with Mr McGuinness' candidacy if he disclosed some of his activities with the IRA.
He referred specifically to the death of Patsy Gillespie in the so-called proxy bombing of a Derry army barracks in 1990.
Mr Gillespie, who worked as a cook in the barracks, was made to drive a bomb into the complex while his family was held hostage. It exploded, killing him and five soldiers.
Speaking on Radio Ulster's Good Morning Ulster, McGuinness said he had "absolutely no involvement" in the attack.
The Mid-Ulster MP has received support for his candidacy from the brother of an IRA bomb victim.
Mark Eakin, who lost his eight-year-old sister Catherine in the 1972 Claudy bomb attacks, said Mr McGuinness, then second-in-command of the Provisionals, would make a good head of state.
He said: "You have to look at the broader picture - is it a bad thing for him to be the Irish president? I don't think so.
"He now wants to have a good Ireland. I think everybody has got to step back and bite the bullet."
DUP MP Gregory Campbell said that Mr McGuinness' past should not be forgotten.
He said: "He said in answer to a reporter that he had made peace wherever he had gone.
"I don't know what sort of place he thinks people are living in. Northern Ireland and Londonderry in particular are picking up the pieces from the 30 years that we endured because of his organisation."
In the Irish general election earlier this year, Sinn Fein won 10% of the vote and 14 seats in the Irish parliament - its best performance in the modern era.
Despite political commentators indicating that he will have to win a considerably higher percentage to prevail in the 27 October poll, Mr McGuinness is some bookmakers' favourite and said he was in the contest to win.