Irish Taoiseach Micheál Martin has come under sustained criticism after dismissing growing calls for Irish unity.

Sinn Féin leader Mary Lou McDonald said his remarks were “completely out of step with political reality across the island”, arguing that the government was failing to show leadership on what she described as the most significant constitutional issue facing the State.

Her criticism followed comments made by the Taoiseach during an interview on TG4, in which he said there was ‘not much substance’ behind preparations for a referendum on Irish unity. Instead, he promoted projects such as the cross-border bridge linking Warrenpoint in south Down to Omeath in north Louth as part of his ‘Shared Island’ initiative.

Ms McDonald TD said the remarks were “both wrong and revealing”.

“It shows a government that is content to drift, rather than lead, on the most important constitutional question facing our country,” she said.

She rejected the suggestion that Irish unity amounted to a political campaign rather than a concrete goal.

“Irish unity is not just a ‘campaign’. It is a democratic objective enshrined in the Good Friday Agreement. It is grounded in the lived experience of people across this island who want better public services, economic opportunity, political stability and a future free from division.

“The responsibility to prepare for constitutional change rests squarely with the Irish Government. On that front, this government has failed.”

While welcoming practical cross-border cooperation, Ms McDonald said such projects could not replace political preparation.

“Connections between communities matter. Reconciliation matters. Sinn Féin has consistently championed dialogue, respect and partnership. But building a bridge at Narrow Water, while positive, is not a strategy for constitutional change. Cultural exchanges and poetry readings are no substitute for serious preparation.

“The Shared Island initiative, while useful in parts, is not a plan for unity. It does not address the core questions of healthcare, taxation, public services, rights protections or economic transition in a new Ireland. These are the issues that require detailed, structured planning now – not in some vague future beyond 2030.”

She also challenged the Taoiseach’s view that there was “no prospect” of a referendum before 2030, saying it failed to reflect demographic and political change.

“Public opinion is shifting. The conversation is advancing. Citizens’ assemblies, independent research, and cross-community dialogue are all pointing to the need for structured preparation. Pretending that change is not happening will not stop it.

“The Good Friday Agreement provides a clear democratic pathway. It is not for any Taoiseach to dismiss that pathway because it is politically inconvenient.”

Responding to the Taoiseach’s suggestions that unity talk is premature, she said leadership required forward planning rather than delay.

“Leadership means preparing for the future, not postponing it. The role of the Irish Government should be to plan, to inform, and to engage people honestly about what unity would look like – socially, economically and politically.

“Sinn Féin will continue to work constructively with all communities on this island. Irish unity must be achieved by consent, through peaceful and democratic means, with protections and guarantees for all traditions.

“The real question is not whether there is ‘substance’ behind unity. The real question is why this government refuses to provide it.”

She said the coming years represented a decisive period.

“This is a defining decade. The government can either lead responsibly and prepare for constitutional change, or it can continue to pretend that the conversation is not already well underway. Sinn Féin will not wait for complacency to catch up with reality.”

The debate comes as Conradh na Gaeilge, the country’s largest Irish language organisation, has pledged to work towards a united Ireland. Delegates at its ard-fheis in Belfast voted overwhelmingly to amend its constitution to support unity “in the interests of the Irish language and the Gaeltacht”.

Further criticism of the government’s position came from Donegal TD Pearse Doherty, who was speaking at a Sinn Féin event in Cork. He said the failure to prepare for unity ignored growing momentum but would not halt it.

Constitutional change, he said, offered the chance to build “a real republic worthy of all our people - of every tradition and background”.

“The Taoiseach suggests that the growing call for a unity referendum lacks depth or seriousness. That assessment is deeply misguided. The demand for constitutional change is not theatre or tactics - it reflects a real and accelerating shift in public opinion across this island.

“Irish unity is not a mere slogan. It is a democratic provision within the Good Friday Agreement and a legitimate aspiration held by a growing number of citizens who want a more effective, fair and united Ireland.

“The Irish government has a responsibility to prepare - to examine the economic, fiscal and public service implications of unity, to facilitate structured dialogue, and to provide citizens with clear, credible information about what a new Ireland would look like.

“Leadership requires foresight. Ignoring momentum for change will not make it disappear. The responsible course of action is to engage with it honestly and constructively.

“The Good Friday Agreement provides a democratic pathway. The role of the Irish government is not to downplay that pathway but to ensure that, when the time comes, the people are equipped to make an informed decision.”

He said unity could deliver major economic benefits through coordinated infrastructure, reduced duplication and balanced regional development.

“The economic dividend would be substantial,” he said. “But growth alone is not justice. The benefits of unity must serve ordinary people - affordable homes, secure jobs, properly funded public services and thriving communities.”

Mr Doherty also stressed the need for inclusivity and respect.

“Unionists and Protestants are central to this conversation,” he said. “Their British identity, culture and history must be respected. Unity is not about absorption or erasure - it is about shaping a new future together.”

He said many working-class communities in the North, including Protestant areas, had not benefited from the status quo and that unity rooted in social and economic justice offered “something better than remaining the poor relation of Brexit Britain”.

He concluded: “Unity will not happen by accident. It will happen because we prepare, because we persuade, and because we organise,” he said. “The only question is whether leadership will match this moment with courage.”