The families of Israeli hostages and thousands of their supporters arrived in Jerusalem on Saturday at the end of a five-day march to confront the government over the plight of those taken captive by Hamas in Gaza.

An estimated 20,000 marchers, including well-wishers who joined the procession along the main Tel Aviv-Jerusalem highway, want to put pressure on the government "to do everything they can to bring the hostages back", said Noam Alon, 25, clutching a photograph of his abducted girlfriend, Inbar.

"We are expecting them to meet with us, we are expecting them to tell us how they are going to do it," he said. "We cannot wait any longer, so we are demand(ing) them to do that now, to pay any price to bring the hostages back."

Around 240 people - from babies to grandparents and including foreign nationals - are believed to be in the Gaza Strip after being taken hostage by the Islamist group during an Oct. 7 raid on southern Israeli villages and army bases in which 1,200 people were killed.

Many relatives and friends of the missing fear they will come to harm in Israeli attacks on Gaza designed to destroy Hamas. The government says the offensive improves the chances of recovering hostages, perhaps via a mediated prisoner exchange.

"I feel that people think that there is time, but for babies and for elderly people with difficult complex needs, there's no time, time is running out rapidly," said London-based artist Sharone Lifschitz, whose 83-year-old father was abducted.

Many Israelis blame their government for being blindsided by the Hamas assault.

Among those who marched to Jerusalem was centrist opposition leader Yair Lapid, who has been mostly supportive of the war but has demanded the resignation of Prime Minister Benjamin Netanyahu.

Miki Zohar, a member of Netanyahu's cabinet and party, was heckled on Friday when he visited the marchers at a rest stop.

Hamas, which in the early days of the war threatened to execute hostages in retaliation for Israeli air strikes, has since said some of the hostages have been killed in attacks on Gaza.

That has stoked the anxiety of campaigners and relatives calling on the Israeli government to speed up any prisoner swap, and frustration with Netanyahu's insistence that discretion is required around the Qatari- and Egyptian-mediated negotiations.

"It's impossible that there are 240 kidnapped people and the government -- our government -- isn't talking to (the relatives), isn't telling them what's going on, what's on the table, what's on offer, what are the reasons for and against. Nothing," said campaigner Stevie Kerem.

Despite the exhaustion and frustration on display, one marcher allowed herself a note of optimism.

"I'm happy with the fact that we have the whole of Israel around us," said Meirav Leshem-Gonen, whose daughter Romi, 23, is among the hostages. "This is what will count in the end."