Chanting slogans against the government and Prime Minister Benjamin Netanyahu, the demonstrators carrying Israeli flags gathered in the commercial hub shortly after Gallant's dismissal was announced.

Protesters also blocked traffic and lit fires on the Ayalon highway in Tel Aviv, with some wearing "Bring them home now!" t-shirts referring to the hostages.

They held up signs with slogans such as "We deserve better leaders" and "Leaving no one behind!" and one protester wore handcuffs and a face mask with Netanyahu's likeness.

"Bibi traitor! You're guilty" chanted some, referring to Netanyahu and blaming for failing to prevent the Hamas attack on October 7 last year.

"We, the protesters, believe that Gallant... is actually the only normal person in the government," said 54-year-old teacher Samuel Miller, slamming Netanyahu's administration for opening "new fronts in uncalled-for wars".

"He's doing nothing to safeguard our peace, the peace of the Palestinians, the peace of everybody in this region," Miller told AFP.

He also criticised Netanyahu's government for "doing absolutely nothing to free the hostages" still held in Gaza.

Foreign minister Israel Katz took over the defence portfolio on Tuesday, after Netanyahu fired Gallant over eroded trust over the past months of the Gaza war.

- 'Endangering Israel's security' -

An Israeli group campaigning for the release of hostages in Gaza on Tuesday expressed "deep concern" over the sacking and urged Katz to "prioritise" a deal to free the captives.

"We expect the incoming defence minister, Israel Katz, to prioritise a hostage deal... to secure the immediate release of all hostages," the Hostages and Missing Families Forum said in a statement.

Gallant also called on the government to bring home the hostages, saying in a televised speech: "We must do this quickly, while they are still alive."

Einav Tzangauker, whose son Matan is among the hostages, was among those protesting against Netanyahu in Tel Aviv.

"If it is possible to replace a defence minister in the middle of a war, then it is surely possible to replace a prime minister who is unqualified to bring back the hostages," she told Israel's Channel 12.

Netanyahu "is intentionally endangering Israel's security and all that because of a dispute between him and Gallant on how to continue the war," she added.

The war erupted on October 7, 2023 after Palestinian militants attacked Israel, resulting in 1,206 deaths, mostly civilians, according to an AFP tally of Israeli official figures.

Israel's retaliatory campaign has killed 43,391 people in Gaza, a majority of them civilians, according to figures from the Hamas-run territory's health ministry the United Nations considers reliable.

During the October 7 attack, Palestinian militants seized 251 hostages, of whom 97 are still in Gaza. The Israeli military says 34 of them are dead.