Israeli Prime Minister Ariel Sharon (search) appealed Thursday to his Likud Party (search) to support a crucial proposal that would let him broaden his coalition to ensure the survival of his shaky government and his plan to withdraw from the Gaza Strip (search) next year.

Members of the Likud Central Committee (search) were casting ballots throughout the day to decide whether to allow Sharon to begin negotiations to bring the opposition Labor Party into the coalition.

High turnout was expected to favor Sharon since a majority of the 3,000-member committee appeared to support his proposal. Analysts said the vote was the most important the ruling party has held in decades.

In a series of rare morning radio interviews, Sharon tried to persuade his supporters not to become complacent or take victory for granted.

"I want to call again on the Likud members to come and vote. This is very important," Sharon, who has lost several key votes in his hard-line party, told Army Radio.

Likud had banned Sharon from talking with Labor in August. But Sharon's grasp on power has weakened considerably since then. Last month, Sharon fired the moderate Shinui Party from his government in a dispute over funding for ultra-Orthodox parties, leaving him with only 40 seats in the 120-seat Knesset.

Many Likud officials who had opposed a coalition with Labor, changed their position in recent days, fearing a government collapse would force early elections that could cost the party seats.

Sharon also hoped to avoid early elections. A Likud primary before that vote would pit him against Finance Minister Benjamin Netanyahu (search) in a bitter race for party leader he is not guaranteed to win.

A new election also could delay — or scuttle completely — Sharon's plan to pull out of the Gaza Strip and four West Bank settlements next year.

Sharon railed against his opponents in Likud on Thursday, saying they should stop trying to sabotage Israel's historic efforts to withdraw from Gaza and remove Jewish settlements.

"The time has come to stop this incessant harassment and to allow the government to work. It's clear that there is an attempt to prevent the government from carrying out its plans, its fight against terror ... to prevent the withdrawal from Gaza," he told Israel Radio.

The Gaza withdrawal plan has boosted Israel's international standing and helped its economic situation, he said.

Sharon's plan has become a centerpiece of efforts to restart peace talks with the Palestinians following Yasser Arafat's death last month.

Sharon, who originally conceived of the plan as a unilateral measure, has expressed a willingness to coordinate it with the new Palestinian leadership. Egypt also has agreed to help ensure Gaza's stability following an Israeli pullout.

Hard-liners oppose an alliance with Labor, which they consider too dovish.

"We are not against the Labor Party, just (against) turning the Likud Party into the Labor Party, and that is what the prime minister has done over the past two years," Uzi Landau, a Likud lawmaker who opposes the withdrawal plan, told Army Radio.

Results of the poll were expected early Friday.

A loss for Sharon would limit his options. He could form a minority government with the ultra-Orthodox parties, relying on the support of dovish opposition parties to prop up his government so it can carry out the withdrawal. He can call elections. Or he can defy his party, a risky move for his political career.

"This evening's vote could bury Sharon under a pile of rubble, after which it will be hard to get up," analyst Nadav Eyal wrote in the daily Maariv.