Ireland’s political leaders have clashed on housing, public spending and the government’s response to war-ravaged Gaza in the first TV leaders’ debate of the general election campaign.

The RTE leaders’ debate, which was scheduled for two hours long but ran overtime, covered coalition options, housing, cost of living, climate, migration, and a bill to ban imports to Ireland from illegal Israeli settlements.

The debate opened up with possible future coalition options, with Ireland’s premier and deputy premier repeatedly making clear their opposition to entering government with Sinn Fein.

Standing together in the RTE studio, after a random draw placed them side by side, Taoiseach and Fine Gael leader Simon Harris and Tanaiste and Fianna Fail leader Micheal Martin were asked about their intentions if both secured a mandate to return to government.

Fine Gael and Fianna Fail served together for the first time in the last administration, a historic coalition that brought together two parties forged from opposing sides of Ireland’s civil war of the 1920s.

The Green Party served as a junior partner in the government.

Sinn Fein won the popular vote in 2020 but a failure to run enough candidates meant it did not secure sufficient seats in the Dail to give it a realistic chance of forming a government.

Sinn Fein President Mary Lou McDonald is hoping to secure a breakthrough on polling day on November 29 that would see her party enter government south of the border.

Tanaiste and leader of Fianna Fail, Micheal Martin (left) and Taoiseach and leader of Fine Gael, Simon Harris during the General Election leaders’ debate (Niall Carson/PA)

As the debate involving 10 party leaders and deputy leaders began on Monday night, Mr Harris ruled out a coalition with Sinn Fein.

“I don’t mean that in any sort of pejorative sense, it’s just being honest with the electorate,” he said.

“I think it’s important to tell people where you stand on a policy basis and give people choices.

“If people vote for Sinn Fein to be in government, that’s their choice, but my party doesn’t wish to be a part of any such government.”

Mr Martin was asked the same question.

He said there were major policy differences between Fianna Fail and Sinn Fein.

“They’re not serious when it comes to pro-enterprise policies,” he said.

“They opposed our entry into the European Union and every treaty since.”

Ms McDonald insisted it was for the electorate to decide which party had a pathway to power.

“I think this election is potentially a historic one,” she said.

“Because for the very first time, there is the choice, the opportunity of a government led by neither Fine Gael nor Fianna Fail, but rather led by Sinn Fein.”

Green Party leader Roderic O’Gorman said his party had delivered in government and said they had spoken to Sinn Fein on policy priorities after the last general election but it “wasn’t clear to us that there was an alternative government available at that period”.

Labour leader Ivana Bacik said people were looking for “constructive change” and said she would speak to “like minded” centre-left parties.

“We have significant policy differences in Labour with the three biggest parties,” she said.

Social Democrats’ deputy leader Cian O’Callaghan said they would speak to all the parties after the election.

Aontu leader Peadar Toibin prompted protestations when he said: “I just think it’s incredible.

“We’re about 10 minutes in, and nobody’s been able to give a straight answer at this stage.”

He added that they would not go into government with Fine Gael, accusing them of having “incinerated people’s money through waste” or the Greens, due to “the damage that’s been done to rural Ireland in terms of the pressure put on farmers”.

He also called Fianna Fail an “empty hollow husk” and said of Sinn Fein “we don’t know what they stand for”.

Michael Collins said Independent Ireland would not whip its TDs on moral issues, but they would be on a programme for government, and they would not rule out any party.

People Before Profit’s Richard Boyd Barrett said that they wanted “to end 100 years of Fianna Fail and Fine Gael rule and see a left government for the first time in the history of this state”.

He said there should be a left alliance, to which Ms Bacik agreed, before Joan Collins of Right To Change said she would speak to all “left progressive groups” who are a “serious current”.

While Mr Harris and Mr Martin did not row with one another during the debate, disagreements broke out between Mr Martin and Mr O’Gorman on climate policies, and also between Ms Bacik against both Mr Boyd Barrett and Ms McDonald on the carbon tax.

Ms McDonald also said it was “astonishing to hear” Fine Gael and Fianna Fail suggest that the first-time buyers’ Help-to-Buy was a “panacea” to the housing crisis when it was “an admission of failure and defeat”.

“Schemes like that and interventions like that should only ever be temporary,” she said.

Mr Toibin said the government was “tied up in knots” on housing and proposed an “Operation Shamrock”, which would look to attract construction workers from abroad.

People Before Profit’s Richard Boyd Barrett said that a failure on housing was because the state “has allowed people driven by profit to come to control the housing sector in this country – vulture funds, property investors, speculators”.

Mr Martin said “Fianna Fail has made a difference on housing” and said that a state construction company would “take years” to establish and accused it of being “more delay, more disruption”.

He added: “Richard, your proposals would destroy the construction industry,” to which Mr Boyd Barrett said Mr Martin’s party had “destroyed the economy”.

Ms McDonald also criticised a Fine Gael proposal on a savings fund for infants not yet born when there are 4,500 children homeless and others on waiting lists for spinal surgery.

Mr Harris said “how dare you” at the accusation of “faux” concern for children by Ms McDonald, to which she added, “nobody has a monopoly on compassion”.

“But here’s the thing, you and Micheal Martin have had a monopoly on power for a very long time, and yet here we are,” she said.

Mr O’Callaghan said that if every measure in the government’s climate action plan was implemented, “we still wouldn’t meet our emissions target reduction”.

Ask Mr O’Callaghan said “I think the government are leading farmers down the garden path by saying, ‘Oh, we can keep this in place, and definitely that will not be the case”, Mr Harris interjected to say “of course we can keep it in place”.

Ivana Bacik said it was “hard to take parties seriously on climate where they do not support a carbon tax”.

This prompted protestations from others including Mr Boyd Barrett, who said it would penalise working people, with Ms McDonald agreeing.

Michael Collins said he was “absolutely” serious about climate change and said that the retrofitting of homes was not being delivered fast enough.

Joan Collins said that people had been “demonised” over climate action and said there needed to be “social intervention into climate”.

When asked would they support pending legislation to ban imports from illegal Israeli settlements in Palestine, all party leaders said yes.

“You went to the White House, you bottled it,” Ms McDonald said during this part of the debate, to which Mr Harris asked her if wasn’t she at the White House as well, to which Ms McDonald said he was visiting as Taoiseach.