The withering attack by Minister of State Brian Hayes -- he accused Sinn Fein of "hyping" a "very minor" event -- comes as the party is attempting to distract attention from a controversy arising out of its misuse of taxpayers' money.
The Sunday Independent can today reveal that Sinn Fein is facing the possibility of having to repay more than €500,000 to the Exchequer after it was exposed last week as having paid activists out of cash claimed for travel expenses.
The practice clearly amounts to a breach of Oireachtas rules, introduced in 2010, which require that TDs and senators return unspent travel expenses.
He said: "Whilst the Sinn Fein spin machine goes into overdrive trying to over-hype a photograph, they have yet to answer many legitimate questions which the Irish people expect answers to, both in terms of how they use public funds in relation to hiring of staff, and also the many outstanding questions that citizens of our country put to Martin McGuinness during his failed presidential bid."
Mr Hayes also accused RTE News of "dancing to Sinn Fein's tune" by giving such prominence to a so-called "historic" handshake between the Queen and the Northern Ireland Deputy First Minister, Mr McGuinness.
"The idea that the former hard man of the IRA is having a fit of the vapours over meeting the Queen is rather pathetic. It's all about Sinn Fein milking headlines. The question for RTE is this: why are you dancing to Sinn Fein's tune?" Mr Hayes asks in the Sunday Independent today.
Sinn Fein finance spokesman Pearse Doherty put €8,000 of unspent travel and accommodation expenses toward hiring part-time party workers; foreign affairs spokesman Padraig MacLochlainn has also confirmed that he used unspent expenses in the same way.
Significantly, both Mr Doherty and Mr Mac-Lochlainn signed certificates last year to declare that they had only used the expenses to pay for travel and accommodation.
The maximum penalty for those found to have contravened the Ethics in Public Office Act is a 30-day suspension from the Dail and a freeze on salary payments for this period.
To date the Standards in Public Offices Commission (Sipo) has accepted the bona-fides of Sinn Fein's claim that this policy does not constitute an actual donation to Sinn Fein.
However, in the wake of the declaration by the Sinn Fein TD Sandra McLellan that she returned all unspent expenses, the Sipo has written to Sinn Fein and Ms McLellan to elicit further clarification.
The Sipo is understood to be considering examining the rules governing the issue with a view to "revisiting" the controversy with other Sinn Fein TDs and senators.
There is understood to be a strong view within the Sipo that the issues raised could merit a wider inquiry into SF use of taxpayers' money.
Although Sinn Fein has promised to co-operate with any such inquiry, correspondence seen by the Sunday Independent states that answers to queries from the Sipo are "still awaited".
The correspondence also states that, while the Sipo is not yet in a position to comment, the standards watchdog was of the view that "all political parties and members of the House are well aware of the legislation governing donations relating to donation thresholds and limits".
The public's attention has been diverted from the controversy, however, by publicity surrounding the scheduled handshake to take place in the North on Wednesday.
"We all know Sinn Fein has been playing a cheap little media game on this issue," Mr Hayes said. He accused Sinn Fein of "showing bad judgement" by not attending a State dinner for the Queen at Dublin Castle during her successful visit to Ireland in May last year.
Mr Harris added: "I think it is astonishing the disproportionate amount of coverage that Sinn Fein are receiving for engaging in a civilised act which is years overdue.
"It is clear that they are now a partitionist party in a very real way; protesting against the Queen's visit to the Republic whilst happily greeting her in Northern Ireland.
"Yet again with Sinn Fein it's one policy in the North and the complete opposite in the South. Such hypocrisy would not be tolerated from any other political party."
Mr Harris also said: "By all means, let Martin McGuinness shake the Queen's hand and as a result run to catch up with the rest of Irish society -- but can we please then get back to real politics?"
The relevant legislation on political donations states that 'any member of the Houses of the Oireachtas (ie TDs and senators) or indeed any individual that donates in excess of €6,348.69 to a political party during a calendar year is in breach of that Act'.
In a scenario where a party receives a donation in excess of the limit 'that part of the donation that exceeds the limit must be returned to the donor' or alternatively the party should 'within 14 days of receipt notify the Standards Commission of receipt of the donation and remit the excess to it'. Any such excess is then forwarded to the Minister for Finance.
Further controversy surrounded the party last week when FG Senator Tom Sheahan claimed gardai had been intimidated and insulted at the Sinn Fein Ard Fheis in Killarney, Co Kerry. Mr Sheahan said that a garda had told him that the organisers had "tried to dictate what they wanted from the garda organisation".
He said in the Seanad last week that gardai had been told by Sinn Fein that "they did not want any member of the Garda Siochana in plain clothes".
The FG senator also claimed that when "a member of the Garda Siochana died in tragic circumstances in Co Kerry recently, a member of Sinn Fein said to a friend of mine in the Garda Siochana that they would have done a much cleaner job".