The Irish Government cannot “ram through” a Bill banning imports from illegal Israeli settlements on Palestinian land if it is unconstitutional, Ireland’s deputy premier said.

There is a disagreement between the Irish Government and opposition parties over how quickly the Occupied Territories Bill can be amended and passed ahead of a general election.

It is expected that the Dail parliament will be dissolved by the end of the week and polling day will be at the end of the month.

Ireland’s deputy premier, Micheal Martin, said the Occupied Territories Bill needs to be substantially amended to make it legally robust and will not be ready by the end of the week.

He said the amendments would be ready for the next government.

Opposition politicians have accused the Government of delaying the passage of the Bill after years of stalling.

Independent Senator Frances Black’s Bill, tabled in 2018, has been frozen for years in the legislative process due to concerns that it would breach EU law.

But the Irish Government has said that an advisory opinion by the International Court of Justice (ICJ) in the summer, that declared Israel’s occupation of Palestinian territories illegal under international law and that countries should not aid nor assist the illegal settlements, has changed the context.

The opposition has urged the Government to pass the Bill before an election is held, with Sinn Fein and the Social Democrats offering time in the Dail this week to do so.

Speaking on Tuesday, Tanaiste and Foreign Affairs Minister Mr Martin said it was an “extraordinary position” to ask to “ram a Bill through that is, as currently written, unconstitutional”.

In an appearance before the Oireachtas Foreign Affairs committee, Mr Martin told TDs and Senators that while the ICJ opinion changed “the legal context for the Bill”, it did not make it legally airtight or “a slam dunk”.

“I cannot ram a Bill through that is unconstitutional,” he said.

“This will be challenged, this could go right into the European courts, and the least we could do is produce a Bill that would be robust enough to navigate such a potential journey.”

He said that the advice from the Attorney General several years ago was that if the EU does not take measures to limit or prevent trade with illegal Israeli settlements, there are “exceptional” grounds in EU law that could allow countries to take action.

After decades of theft, dispossession and displacement, and in the context of an ongoing genocide in Gaza, this Bill is the absolute least we can do

He said they had been advised that the provision in EU law can only be compromised on exceptional grounds of public policy, but it would be unusual to use that argument to comply with international law.

Mr Martin said: “What has not changed is the European Union’s exclusive competence in the field of trade for all of its member states, including Ireland. It is against this background that the Taoiseach asked the Attorney General to provide updated advice in relation to this Bill.

“However, it is important to understand that these grounds have never been used by a member state before in similar circumstances. There therefore remains a legal risk if we do take our own domestic measures.”

The author of the Bill, Frances Black, also addressed the committee, telling members that passing the Bill “should not have taken this long”.

“If (the ICJ ruling) is what can finally unlock things, then I truly welcome it.

“We shouldn’t waste any more time, we must focus on getting this legislation passed as soon as humanly possible.

“After decades of theft, dispossession and displacement, and in the context of an ongoing genocide in Gaza, this Bill is the absolute least we can do.”

Christian Aid Ireland’s Head of Policy and Advocacy Conor O’Neill told the committee that a lot of the amendments that had been discussed “are not enormously challenging”.

He said that when the Bill was initially drafted, it was done to apply to an occupied territory anywhere in the world, if there was support within the Oireachtas for it and clarity from international courts on the matter.

But since the Bill is being redrafted to reflect the ICJ opinion, it will now focus on Palestinian territories.

“If that was done, the main constitutional arguments that have also been raised would, by default, cease to apply.”

He also said that any distinction between banning physical goods but not services “would be arbitrary, both politically and legally”.

Sinn Fein foreign affairs spokesperson Matt Carty accused the Government of attempting to “delay and frustrate” the passage of the Bill.

“You have told us that substantive amendment needs to be made to most, if not all of, the provisions of the Bill.

“In fact, you have already directly contradicted Senator Frances Black, who says that the requirements are technical changes.”

Chairman of the committee and former justice minister Charlie Flanagan asked Mr Martin for correspondence from the attorney general Rossa Fanning to explain the reasoning for the amendments to the Bill.

Mr Martin responded that because Mr Fanning’s advice “points to potential lines of attack from people who might want to undermine the Bill”, it should not be shared.

“So you furnish that with more than 10 people or whatever and it gets in the hands of those who might take a case against it, that would weaken our position collectively as a nation in defending such a Bill.”

He added: “Passing this Bill will not stop Israel’s behaviour, unfortunately.”