UN human rights chief Volker Turk on Thursday called on Israel to heed those demonstrating for "the defence of democracy and fundamental freedoms" in the face of the controversial judicial overhaul.
The new legislation curbs judicial review by Israel's top court of some government decisions, and critics fear it could pave the way to more authoritarian government.
Prime Minister Benjamin Netanyahu's governing coalition pushed through the key plank of its controversial overhaul package on Monday, sparking legal challenges and clashes on the streets.
Turk said he had been closely following developments, noting that for months, people from across Israeli society had been "demonstrating peacefully, building alliances for the defence of democracy and fundamental freedoms".
"This broad-based social movement has grown over the months to stand up for human rights and preserve the democratic space and constitutional balance so painstakingly built in Israel over many decades," he said in a statement.
"It demonstrates the extent of public disquiet at the extent of fundamental legislative changes."
Noting the petitions before the Supreme Court, Turk said it was essential for the court to be given space to decide the questions before it, according to due process of law, free from political pressure or interference.
"I urge those in power to heed the calls of the people in this movement - people who have put their trust in the enduring value of an independent judiciary to effectively hold the other branches of government to fundamental legal standards and - ultimately - protect the rights of all people," Turk said.
The legislative changes scrap the "reasonableness" clause used by the Supreme Court to overturn government decisions which are deemed unconstitutional.
The controversial overhaul has split the nation and drawn criticism from allies abroad.