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 bid to change the judiciary has plunged Israel into one of its worst political crises, sparking nationwide protests, denting the economy and stirring concern among Western allies.

Carrying blue and white Israeli flags, a kilometres (miles) 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.

As night fell, they rallied outside parliament ahead of a Sunday debate and subsequent vote on the bill, which would limit the Supreme Court’s powers to void what it considers “unreasonable” government or ministerial decisions.

Tens of thousands more protested across the country, including around 100,000 people in business hub 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 premier on Saturday to call off the vote and voiced support for reservists who have said they will no longer serve in protest against the government’s campaign.

Netanyahu, who is on trial for corruption that he denies, has said he has been striving for broad agreements and has placed the onus on opposition parties to make compromises.

Defence Minister Yoav Gallant said on Friday 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.