Tens of thousands of Israelis opposed to a judicial overhaul sought by Prime Minister Benjamin Netanyahu marched to Jerusalem on Saturday, as pressure mounts on his right-wing government to scrap a bill that would curtail the Supreme Court’s powers.

The government’s bid to reform the judiciary has plunged Israel into one of its worst political crises, sparking nationwide protests, denting the economy and stirring concerns among Western allies.

Carrying blue-and-white Israeli flags, a kilometres-long column of protesters hiked up the winding highway to Jerusalem under a scorching summer sun to the sounds of beating drums and anti-government chants.

“Democracy is not as certain as it used to be,” said Ido Golan, a protester from central Israel who joined with his partner and two young children, one on his back in a baby carrier. “It’s very important for us and also for them to know we did what we can to save the democracy.”

The protesters had walked for several days through a heatwave, with their numbers swelling as they reached the city gates.

Tens of thousands more protested across the country, including around 100,000 people in the business hub of Tel Aviv.

Netanyahu’s religious-nationalist coalition says the bill, which parliament is scheduled to vote on by Monday, is needed to balance out the branches of power.

Critics say the amendment is being rushed through parliament and will open the door to abuse of power.

Polls suggest widespread misgivings among Israelis, and Washington has urged Netanyahu to seek consensus on any reforms, which should also keep the judiciary independent.

The crisis has even sown divisions within the military, long viewed as an apolitical melting pot for a fractious society, with concerns about war readiness voiced on both sides of the debate.

Dozens of former security chiefs, including military, police and Mossad heads, some of whom had served under Netanyahu, published an open letter to the prime minister on Saturday to call off the vote and to voice support for reservists who have said they will no longer serve in protest against the government’s campaign.

Defence Minister Yoav Gallant said on Friday that he was working to reach a consensus. Energy Minister Israel Katz told N12 News the coalition would not bow to pressure from reservists trying to strong-arm a democratically elected government.