Israeli opposition politicians and Palestinian representatives have drawn up a draft peace agreement which they regard as a viable alternative to the international plan known as the roadmap.
Israel's left wing has set out to prove Ariel Sharon wrong
The unofficial plan - known as the Geneva Accord - was finalised over the weekend during a meeting in Jordan.
It comes after two years of secret negotiations, backed by human rights activists and intellectuals, and supported by Swiss diplomats.
Those involved hailed it as a blueprint to end the Middle East conflict, but Israeli Prime Minister Ariel Sharon has angrily denounced the proposal, accusing left-wing Israelis of trying to bring down his coalition government.
The BBC Jerusalem correspondent, Orla Guerin, says Mr Sharon has long maintained there is no-one to talk to on the Palestinian side.
The left-wingers have set out to prove him wrong, but she says the public on both sides has grown weary and regard the plan as no more than a wish list with no legal standing.
The full details of the plan are due to be released when the initiative is formally adopted in Geneva next month, but sources say there is a key trade-off at its heart - Palestinians would not demand the right of return for refugees.
In exchange, they would get sovereignty over one of the most disputed religious sites in the Middle East, Jerusalem's Temple Mount, known to Muslims as Haram al-Sharif.
The Palestinians involved, including former ministers, are reported to have the backing of the Palestinian leader Yasser Arafat.
They, along with their Israeli counterparts, say the accord is aimed at generating public interest and support.
The BBC's Barbara Plett, also in Jerusalem, says that the plan does signal to the Israeli public that there is an alternative to the military strategy adopted by Mr Sharon.
The negotiators hope the plan will appeal directly to the public
Although opinion polls indicate that while the majority of the Israeli public supports that strategy, there is a growing frustration with its failure to stop the violence, our correspondent says.
But members of the Israeli cabinet have been swift to condemn the plan.
"There is a roadmap, and it is not helpful to make people think there might be something else," Mr Sharon told the Jerusalem Post.
Vow to continue
However, others were far more vitriolic:
Israel's Education Minister Limor Livnat has dismissed those involved saying: "The Israelis who put their names to the plan are marginal people who represent nobody but themselves and who paid the price for that at the last elections.
"These people are the playthings of [Palestinian leader] Yasser Arafat."
That sentiment was echoed by Foreign Minister Sylvan Shalom:
"I wouldn't have expected anything else from the people who gave us the Oslo accords - we're still paying for them today," the Israeli press quoted him as saying.
He was reported to be alluding to the former Israeli justice minister and participant in the new plan, Yossi Beilin, who was a leading player in the drawing up of the Oslo accords.
However, the Palestinian officials involved in the negotiations said that they would work to ensure that the agreement became a reality.
"We are ready to campaign to win support for this plan on the
Palestinian street because we want a better life and we believe we've found a way to achieve it," Palestinian MP Fares Kadura said.