Ireland's Justice Minister has claimed Martin McGuinness' refusal to attend a state dinner for the Queen in Dublin Castle shows he is not fit for the presidency.
Alan Shatter hit out at the Sinn Fein candidate and claimed he could not be a reconciling force given his failure to join the historic banquet.
Mr Shatter, on a trip to Brussels, also described Mr McGuinness' background as "exotic".
"Martin McGuinness has been doing a very important job in Northern Ireland," the minister said.
"But in the context of his capacity to be a reconciling force across the whole island of Ireland I think Sinn Fein's failure, and his particular failure, to embrace the Queen's visit that took place four months ago, his failure to turn up in Dublin Castle to a dinner hosted by President McAleese at a time when Peter Robinson and his wife as Northern Ireland First Minster attended, indicates that he isn't an appropriate person to be our President.
"I think a lot of people would know he has a somewhat exotic background and I think it would be unusual to say the least should he end up being the titular head of the Defence Forces."
Mr Shatter is the second Fine Gael government minister to reject Mr McGuinness' suitability for the office after Phil Hogan, Environment Minister, said he did not think it would be good for the country if the Sinn Fein candidate won the election.
Meanwhile, Senator David Norris is chasing the final three signatures to secure a nomination from Oireachtas colleagues.
Independents Shane Ross, Michael Lowry and Mattie McGrath hold the key to his bid for the presidency with both Mr Lowry and Mr McGrath appearing to suggest they would not block him, and Mr Ross' intentions unknown.
The local authority route is also still open to the Senator and rival Dana Rosemary Scallon.
A number have arranged meetings for Monday, Tuesday or Wednesday morning including Laois, Carlow, Roscommon, Kilkenny, Donegal, South Dublin, Longford, Waterford City and Offaly.
Both candidates need the support of only four councils and two look committed to giving Dana the vote.
Elsewhere an Independent Senator has complained of receiving abusive emails which she said felt like harassment after declining to support Senator Norris's nomination.
In a post on her Facebook page and on Twitter, Senator Jillian van Turnhout said she had decided last July not to nominate Senator Norris.
"I met with David and explained my reasons which he accepted amicably. I have had no reason to change my decision," the children's rights campaigner wrote.
"I would now ask that the emails, phone calls etc would stop.
"While many are polite and well intentioned a number have been abusive and it now feels like harassment. I have made my decision and I will not be changing."
Nominations have to be submitted to officials in the Custom House on Wednesday by midday. They will be verified by a returning officer before the list of candidates is formally announced at 3pm.
If Senator Norris and Dana are successful there will be a record seven candidates.
Sinn Fein's deputy leader hit back at Mr Shatter warning that it was not for him or Fine Gael to decide who is fit for the presidency.
Mary Lou McDonald said the election for the Aras will be decided by the people.
"I find it completely wrong that a government minister would interfere in the democratic process in such a manner," she said.
"It is the people who will decide who is fit for the office of president and not Alan Shatter or the Fine Gael Party.
"Martin McGuinness is a very strong candidate and this is evidenced by the reactions of people like Alan Shatter."