South Africa could have multiple European Union (EU) countries lined up behind its case against Israel at the World Court, even though the EU as a bloc will almost certainly remain on the fence, with its biggest power fiercely opposed to SA's approach.

Ireland will give joining the International Court of Justice (ICJ) Gaza genocide case "very serious consideration", its minister of foreign affairs and defence, Micheál Martin, told broadcaster RTE.  

The caveat: Ireland wants to see the case South Africa puts forward first, in order to make a decision based on legal grounds.

Opposition parties in Ireland have pushed the government hard to join South Africa's case as a symbolic gesture.

In Belgium, too, activists and civil society groups have pushed the government to come out in support of the South African application. On Friday, a minister in that country hailed "steps in the right direction" after a meeting which formally endorsed the idea of an ICJ-ordered ceasefire in Gaza, without committing to taking part in the legal process.

"If the International Court of Justice calls on Israel to cease its military campaign in Gaza, our country will fully support it," said the minister of development cooperation, Caroline Gennez.

Many other European countries have not commented on the SA vs Israel case directly, or have spoken of their faith in international law, or have called for a Gaza ceasefire and increased humanitarian aid, without reference to SA's allegations of genocide.

Germany is an exception; it "rushed" to declare its intention to join the case on the side of Israel, saying it opposes the watering-down of the crime of genocide in order to apply it to Israel's military actions in Gaza.

Germany is by a significant margin the biggest economic and political force with the EU, with an economy roughly four times the size of Ireland and Belgium combined.

Like the USA and the UK, Germany's position is that Israel has a duty to protect civilians in Gaza, and that the territory requires more aid than it is currently receiving, but that Israel has not committed genocide in its war on Hamas.

Many potential joiners

Third parties can only intervene once the ICJ has ruled on South Africa's request for preliminary measures, an emergency order (which, South Africa hopes, will go so far as to tell Israel to withdraw from Gaza) that could be delivered by the ICJ judges at any time, but should come no later than early February.

After that ruling, South Africa is due to make its substantive case that Israel is guilty of genocide, the adjudication of which will likely take years. During that process, any of the other parties to the Genocide Convention can join the matter, on the basis that all of them are affected by the way the court interprets the convention.

More than 150 states have ratified that convention.

In the ICJ case on genocide between Ukraine and Russia, 32 states have intervened. Ireland, Belgium and Germany are among those. South Africa is not.

The nature of adversarial matters means it is almost inevitable that third parties come out in support of one side or the other, legal scholars say, even though third parties join on a theoretically neutral basis.

Joining World Court cases often have a political objective, and those lobbying Belgium and Ireland say they want to see their countries show support for the South African case. But politicians in various countries have intimated that they fear being accused of antisemitism, and want to be clear on SA's exact approach before associating themselves with it.