It follows Leo Varadkar's shock announcement that he was stepping down.

After receiving a series of endorsements, Mr Harris confirmed his candidacy.

He told RTE: "I am ready to step up and I am ready to serve.

"I want to thank everybody for their support and their trust. It means so much to me and I will work night and day. I will give this my absolute all to repay that trust."

He said he wanted to bring "energy and an enthusiasm" to the leadership of the party and added: "I also want to bring my practical life experience.

"I want to work with colleagues, I want to listen, I want to really reconnect with our party right across the country. I want to get back to core principles."

In a statement, Mr Harris paid tribute to the outgoing taoiseach.

He said: "Leo has steered our party and our country through very challenging times including Brexit, the COVID-19 pandemic, and the recent cost of living crisis.

"If given the opportunity, I will give this my all."

If he were to take over from Mr Varadkar, Mr Harris would become the country's youngest ever taoiseach at the age of 37, taking that title from his predecessor.

Heather Humphreys, the social protection minister, and Jennifer Carroll MacNeill, the minister of state, both ruled themselves out on Thursday afternoon, paving the way for Mr Harris.

Justice minister Helen McEntee also confirmed she would not seek the top job as she publicly backed Mr Harris, the minister for further and higher education.

She described him as "a great colleague" and "a great communicator".

"I know he will bring huge energy to this important role," she posted on X.

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Fine Gael minister of state Patrick O'Donovan is also among those who have thrown their support behind Mr Harris.

He said: "I think at the moment, where Fine Gael is, as we're a year out from a general election, we have plenty of time, and plenty of scope to I think rebuild the organisation, refocus on the issues that are of importance to us and I think Simon is best placed to do that."

Both Fine Gael and their largest coalition partner, Fianna Fail, are trailing the main opposition Sinn Fein party in the polls.

Whoever wins the leadership will have up to 12 months before a general election to try to overturn a wide opinion poll deficit.

Others backing Mr Harris include Fine Gael TD and junior minister Neale Richmond, TD and former junior minister Frank Feighan, senators Tim Lombard and Michael Carrigy and MEPs Frances Fitzgerald and Maria Walsh.

Enterprise minister Simon Coveney, who ran against Mr Varadkar in the last Fine Gael leadership contest, ruled himself out on Wednesday.

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However, any rival candidate still has until Monday to enter the race.

Mr Harris first became a member of parliament at the age of 24, after being elected as a local councillor in his native county of Wicklow, two years before in 2009.

His public profile rose significantly when he served as the country's health minister during the COVID-19 pandemic.

Before that he also served as a junior minister in the finance department from 2014 to 2016.