Israel's Labour party has voted to join the incoming government of prime minister-designate Benjamin Netanyahu, party officials said Tuesday, giving a centrist tone to a hardline coalition.

Senior Labour party official Ofer Eini told Israel's Army Radio that the party's central committee agreed to Netanyahu's partnership offer.

"I'm happy that party delegates have decided to enter the government," Eini said.

Army Radio said the vote was 680 in favour and 507 against.

Labour Leader Ehud Barak faced boisterous criticism from within. Party members at the Labour convention chanted "Disgrace! Disgrace!" after Barak embraced the proposal, many of them arguing that the party should redefine itself in opposition instead of joining with the government.

The contentious vote drove a wedge through the Labour party, as at least six of Labour's 13 legislators were strongly opposed to joining Netanyahu's team, and some may decide to leave the party and remain in opposition.

Former Labour leader Amir Peretz stopped just short of declaring a split. "It will be hard for us to work together, and I assume the government and Benjamin Netanyahu aren't deluding themselves that they're going to get our support," he said.

The vote followed an agreement reached earlier Tuesday between Netanyahu and Barak.

Under the terms of the agreement, Israel will draft a comprehensive plan for Mideast peace, resume peace talks and commit itself to existing peace accords, Labour party officials said.

Barak would likely retain his post as defence minister, while other veteran party lawmakers would be assured ministerial positions.

Israeli President Shimon Peres on Friday authorized a two-week extension for Likud party Leader Netanyahu to form the country's next government, giving him until April 3.

Tense march in northern town

Also Tuesday, Israeli ultra-nationalists marched through the northern, mostly Arab-populated town of Umm el-Fahm, demanding residents show loyalty to Israel and setting off stone-throwing protests by Arab youths that police dispersed with stun grenades and tear gas.

No serious injuries were reported, but residents denounced the march on one of Israel's largest Arab communities.

A day earlier, the Jewish ultra-Orthodox Shas party signed on to become the second partner in the Likud-led coalition. Last week, the Yisrael Beitenu party, led by ultra-nationalist Avigdor Lieberman, signed on.

Netanyahu has urged outgoing Foreign Minister Tzipi Livni's centrist Kadima party to join a broad-based "unity" coalition, but she has refused because he hasn't given support for a Palestinian state.

Kadima edged out Likud by a one-seat margin (28-27) in February's parliamentary election, but neither party could command the 120-seat Knesset.

Netanyahu was tapped to form the government because more leaders said they would support him.

Barak, who served as Israeli prime minister from 1999-2001, had initially refused to join a Likud-led coalition, declaring instead his party would serve outside the government as a "responsible, serious and constructive opposition."

With files from the Associated Press