Israeli prime minister-designate Benjamin Netanyahu invited the center-left Labour party to join his coalition on today in an apparent bid to soften an emerging hardline cabinet.
Labour Party chairman Ehud Barak said in a statement that the party should "seriously consider" the offer.
But Labour's secretary-general, Eitan Cabel, said most members would likely oppose joining a coalition including far-right parties Mr Netanyahu has teamed up with, who have opposed US-sponsored talks with Palestinians for a two-state solution.
"The diplomatic, security, economic and social challenges facing Israel make it imperative the Labour party's hierarchy seriously consider (Netanyahu's invitation)," Mr Barak's statement read.
It said that in the event that the party's basic demands are met, he would propose joining the coalition. Reports said this could happen early next week.
The move by Mr Netanyahu, who faces an April 3rd deadline to form a new government, also seemed a last-ditch bid to persuade outgoing foreign minister Tzipi Livni, head of centrist Kadima and a Barak rival, to join his cabinet.
Ms Livni's Kadima party called off talks on a possible coalition with Mr Netanyahu earlier this month after she accused him of not being committed to pursuing the US-sponsored vision of a Palestinian state alongside Israel.
Israel Radio said Netanyahu had offered to keep Mr Barak, a former prime minister, in his current post of defence minister and give Labour another four cabinet seats.
After decades of dominating Israeli politics, Labour has shrunk to 12 seats in the 120-seat parliament following last month's general election. That makes it the fourth-largest party in the Knesset.
But Shalom Simchon, a Barak party ally said Labour faced a dilemma working alongside ultra-nationalist parties teaming up with Mr Netanyahu, such as Avigdor Lieberman, whose party sealed a deal this week with Likud to name him foreign minister.
Though criticised abroad, Mr Lieberman has soared to control of 15 seats in Israel's parliament, making his party Israel's third largest, behind Likud with 27 and Kadima with 28 seats.