The Sinn Féin leader has urged the Government to approve the Occupied Territories Bill without delay.
Mary Lou McDonald was speaking in the Dáil as her party introduced a Private Members' motion calling for the bill to be enacted.
It aims to ban trade between Ireland and Israel's illegal settlements on Palestinian land.
Ms McDonald said the move would chime with the values of Irish people who have stood resolutely and unwaveringly on the side of human rights and justice.
She referred to the Dunnes Stores workers who went on strike in 1984 over the importation of goods from apartheid South Africa.
(President) Nelson Mandela said that because of the action of those workers, ordinary South Africans were shown that people far away cared about their freedom, she said.
"Today that crucible of apartheid is found in Palestine, in the brutality inflicted on its people by the colonising, occupying, dehamanising, criminal Israeli regime," Ms McDonald added.
She said the crescendo of this is "the genocide perpetrated against the children, the women and the men of Gaza".
The Sinn Féin leader said that a watered-down version or a counterfeit bill would represent a "stunning betraual of the Palestinian people".
The party's Spokesperson on Foreign Affairs Donnchadh Ó Laoghaire echoed the remarks, saying: "Now of all times when the very existence of the State of Palestine is being questioned is not the time to walk away from it.
"Now is the time for the Government to put their money where their mouth is."
Mr Ó Laoghaire said that Fianna Fáil and Fine Gael had given commitments in relation to the bill, but "we have seen the walk back and the walking away" since the formation of the coalition.
A new bill, he added, would contain not just technical but fundamental differences and the Government amendment could not be accepted.
Mr Ó Laoghaire said that Israel had been able to act with impunity and "that is why this bill, the Occupied Territories Bill matters. Because it's about applying international law".
Any bill passed must be lawful - Harris
The Tánaiste and Minister for Foreign Affairs said the Government was on the side of humanity and represented the people of Ireland who cared deeply about what they had been witnessing for many years in the Middle East, particularly since the Hamas attack on Israel on 7 October 2023.
But Simon Harris said the motion tabled by Sinn Féin "does not reflect the track record of sustained, pricipled action by the Irish Government on this issue".
He told the Dáil that he was submitting an amendment which set out a range of meaningful actions taken by the coalition and its broad approach to recent developments.
Mr Harris said the Government would progress legislation in relation to the Occupied Palestinian Territories following the July 2024 advisory opinion of the International Court of Justice.
It said that Israel's settlement policies and exploitation of natural resources in the territories were in breach of international law.
"Pass the Bill now sounds great, but there are major legal issues," Mr Harris said, adding: "It's about getting legislation that is lawful Deputy McDonald, not about pretending to do something for the sake of it".
Mr Harris said he was proud of the actions that Ireland has taken and the country is on the right side of history.
The vote on the issue has been deferred until next week.
