Israel's High Court of Justice was hearing petitions on Sunday calling for ultra-orthodox Jewish men to be conscripted to the army, with a ruling either way threatening to cause a major breach in Prime Minister Benjamin Netanyahu's government.
Nine judges were to hear two petitions demanding immediate conscription of ultra-Orthodox men. A ruling is expected only at a later date.
A legal exception exempting ultra-Orthodox – or Haredi – men from military conscription expired around two months ago. The government has been unable to agree on a new law extending the exemption.
The court has ordered the government to stop funding Haredi yeshivas – schools providing Jewish religious instruction – for students eligible for conscription.
Attorney General Gali Baharav-Miara said this week that the government was acting without authority and "violating the express rules of the court" by continuing to allow the exemptions, the Times of Israel reported. According to media reports, tens of thousands of men could be affected.
Elements within Netanyahu's cabinet, which comprises both far right and religious parties - are strongly opposed to the conscription of men from ultra-Orthodox communities.
The law allowing exemption expired last year, with the government extending its provisions to the end of March this year. The government has committed to passing new legislation by July 31, but has thus far been unable to do so.
The strains imposed on Israeli society by the Gaza War have brought the issue to the fore.
Israeli men are called up for three years, and women for two. Conflict over legislation that would have introduced conscription for Haredi men also helped bring down a governing coalition in 2018.
Some ultra-Orthodox men have volunteered to serve in the military. Women from the ultra-Orthodox community are only recruited voluntarily.