Israel's Supreme Court convened on Tuesday to hear petitions to strike down a key plank of the extreme right-wing government's controversial judicial overhaul that has triggered mass protests and divided the nation.
A full 15-judge panel of the top court began hearing pleas against the amendment of the so-called "reasonableness clause" that the government of Prime Minister Benjamin Netanyahu passed through parliament in July.
The amendment limits the powers of the top court to review and sometimes overturn government decisions, which opponents say paves the way to authoritarian rule.
Dozens of noisy protesters gathered outside the court building as the hearing began, banging drums, blowing whistles, chanting and waving Israeli flags.
Since the government unveiled the plans in January, opponents have rallied weekly in their tens of thousands in cities across Israel.
The months-long rallies have been criticised for excluding Palestinian citizens of Israel who make up around 20 percent of the country's population, and ignoring Israel's ongoing attacks on Palestinians in the West Bank and Gaza.
However, Palestinians have also expressed fears over the judicial overhaul's outcome and organised their own protests.
Chief Justice Esther Hayut said there were eight petitions filed against the legislation limiting the "resonableness clause".
"It's clear you think that the duty to act reasonably applies to the government and its ministers," Hayut said, addressing a lawyer representing parliament.
"But who makes sure they indeed do so?"
Protester Batia Cohen said the government was out to "destroy democracy" in Israel.
"They (government) want to be above law, so the only one that protects us from them is the court," said Cohen, 63, who had travelled to Jerusalem from the northern port city of Haifa.
Thousands of protesters chanting "Democracy, Democracy," had also rallied in Jerusalem on the eve of the hearing.
"The amendment to the basic law that will be debated in court today is not a basic law, it's an irresponsible document," opposition leader Yair Lapid said on Facebook.
'Fatal blow'
Netanyahu's administration, a coalition between his Likud party and extreme-right and ultra-Orthodox Jewish allies, argues that the legal changes are needed to rebalance powers between politicians and the judiciary.
Justice Minister Yariv Levin, the main architect of the reforms, said the Tuesday hearing was a "fatal blow" to democracy, since for the first time the court was considering striking down a basic law, legislation that in Israel takes the place of a constitution.
"The court, whose judges select themselves behind closed doors and without a record, is placing itself above the government, the parliament, the people and the law," he said in a statement.
"This is absolutely against democracy. It means that the court has no checks and balances. It's a single ruler."
Israeli media have reported some moves towards a compromise between the government and the opposition, while Netanyahu said Monday he said aimed to "reach a national consensus to restore the balance of power" between the branches of government.
Israel does not have a constitution or upper house of parliament, and the "reasonableness" law was put in place to allow judges to determine whether a government had overreached its powers.
The Supreme Court used the measure in a high-profile ruling which barred Aryeh Deri, a Netanyahu ally, from serving in the cabinet because of a tax evasion conviction.
Opponents accuse Netanyahu, who is on trial on corruption charges he denies, of trying to use the proposed legal overhaul to quash possible judgements against him.
He rejects the accusation.