Simon Coveney received a campaign boost last night when prominent MEP Mairead McGuinness weighed in behind him as Fine Gael members prepared to vote for their next party leader.
Ms McGuinness had been widely suspected to support Mr Coveney but had insisted she would not declare for either candidate until the campaign hustings took place.
However, in a statement, she said she was backing the Housing Minister because he had shown "grit and determination" by staying in the leadership race when others thought he should step aside.
"In sticking to the race, he has shown a particular passion for leadership - and has also demonstrated an important leadership attribute in not giving up when the going gets tough," she said.
"He has taken his message to the country - to the membership - and the party is the better for that open and frank debate about the direction that our party should take," she added.
Meanwhile, Mr Coveney launched an extraordinary attack on Leo Varadkar's "flashy" leadership campaign and raised concerns over how much money has been pumped into his rival's election war chest.
Speaking to the Sunday Independent on the eve of the final leadership debate, Mr Coveney rounded on his opponent and insisted he did not need "slick PR launches" or "fancy T-shirts" to win over party members.
The Housing Minister's intervention came after it emerged that Mr Varadkar was holding secret fundraising events in members-only clubs in Dublin city centre.
"From my own point of view, every penny we've raised in this campaign has been raised in the normal way through the normal rules," Mr Coveney told the Sunday Independent.
"We fundraised for a campaign that is more about message than it is about spin and more about substance than slick PR launches," he added.
Mr Varadkar's spokesman issued a statement insisting all campaign donations received were in line with political fundraising rules.
"Campaigns such as this cost money and donations are a normal part of the political process," he said. "A reception was held during the week for people who had contributed. The party will be supplied at the end of the campaign with details of expenditure in compliance with all State and party requirements."
Before the leadership contest officially began, Mr Varadkar's supporters sought to have a spending cap introduced for candidates - but the proposal was shot down by Fine Gael headquarters.
Mr Coveney said his rival's campaigners accused him of pumping funds into an election war chest as part of an attempt to "paint a picture that wasn't true".
However, since the campaign has begun, it has been clear to onlookers that Mr Varadkar's camp of supperters has put more resources into their man's bid to become the next Taoiseach.
"The very picture they tried to paint of me is exactly what they are doing themselves and I don't think people buy it," Mr Coveney said.
"I think as the campaign has rumbled on, people can see I am about my message, not about slick events or fancy T-shirts.
"It has been a blunt, strong and ambitious message for the country. I think that's what is changing the momentum in this race, not the big spending campaign that we are clearly up against."
Mr Varadkar has held a number of fundraising events recently. These have included a fundraiser hosted by Thomas Lynch, who is chair of Dublin East Hospital Group and whose remit includes St Vincent's University Hospital and the National Maternity Hospital.
'Each week on the Floating Voter, INM's political team discuss the main issues affecting Irish politics, bursting the bubble that surrounds Leinster House.'
Mr Varadkar has also put policies in his election manifesto that Mr Coveney wrote, the Housing Minister claimed.
He said: "Look at Leo's manifesto on the marine and he talks about Ireland having for the first time a full maritime strategy for the country. I wrote that - and I implemented it.
"He talks about Food Wise 2025 as the roadmap for the food industry - I wrote it and I'm implementing it."
Mr Coveney, who previously served as minister for agriculture, food and the marine, insisted he was the best candidate to address the needs of rural Ireland.
He added: "Who do they want as Taoiseach? Someone who has been down and dirty in those communities and has tried to find a way of supporting them or someone who has it in their manifesto, talking about things I've done?"
Mr Varadkar is expected to publish his rural policies at an event in Cavan tomorrow.
Mairead McGuinness's support means Mr Coveney now has the votes of 21 TDs compared to Mr Varadkar's 46.
Mr Coveney's supporters believe they can secure the support of the remaining undeclared voters, who include Taoiseach Enda Kenny, Finance Minister Michael Noonan, Agriculture Minister Michael Creed, MEP Sean Kelly and some TDs.
Fine Gael parliamentary party endorsements for leader
The Fine Gael parliamentary party makes up 65pc of the total electorate.
That makes each of the 73 members' votes worth 0.9pc of the total ballot.
Of the remaining electorate, 230 party councillors account for 10pc, while the remaining 25pc is rank and file members.
|Richard Bruton -Minister||Simon Harris - Minister|
|Frances Fitzgerald - Minister||Damien English - Minister|
|Michael Ring - Minister||Dara Murphy - Minister|
|Eoghan Murphy - Minister||David Stanton - Minister|
|Sean Kyne - Minister||Marcella Corcoran Kennedy - Minister|
|Joe McHugh - Minister||Kate O'Connell - TD|
|Helen McEntee - Minister||Maria Bailey - TD|
|Charlie Flanagan - Minister||Sean Barrett TD|
|Paul Kehoe -Minister||Hildegard Naughton - TD|
|Patrick O'Donovan - Minister||Peter Fitzpatrick - TD|
|Regina Doherty - Minister||Tim Lombard - Senator|
|Mary Mitchell O'Connor - Minister||Jerry Buttimer - Senator|
|Paschal Donohoe - Minister||Paudie Coffey - Senator|
|Heather Humphreys - Minister||James Reilly - Senator|
|Pat Breen - Minister||Colm Burke - Senator|
|Catherine Byrne - Minister||John O'Mahony - Senator|
|Andrew Doyle - Minister||Paul Coghlan - Senator|
|John Paul Phelan - TD||Gabrielle McFadden - Senator|
|Noel Rock - TD||Deirdre Clune - MEP|
|Tony McLoughlin - TD|
|Alan Farrell - TD|
|Michael D'Arcy - TD|
|Tom Neville - TD|
|Josepha Madigan - TD|
|Pat Deering - TD|
|Jim Daly - TD|
|Brendan Griffin - TD|
|Ciaran Cannon - TD|
|Colm Brophy - TD|
|Peter Burke - TD|
|Fergus O'Dowd - TD|
|John Deasy - TD|
|Joe Carey - TD|
|Neale Richmond - Senator|
|Catherine Noone - Senator|
|Paddy Burke - Senator|
|Martin Conway - Senator|
|Michelle Mulherin - Senator|
|Maura Hopkins - Senator|
|Ray Butler - Senator|
|Frank Feighan - Senator|
|Maria Byrne - Senator|
|Joe O'Reilly - Senator|
|Kieran O'Donnell - Senator|
|Brian Hayes - MEP|
|Enda Kenny - Outgoing Party Leader *||Martin Heydon - Party Chairman *|
|Michael Noonan - Minister||Michael Creed - Minister|
|Bernard Durkan - TD||Sean Kelly - MEP|
|Mairead McGuinness MEP|
* Outgoing leader Enda Kenny and party chairman Martin Heydon will not make an endorsement