Sharon also told a parliamentary committee that if the plan is rejected, he will try to form a new government immediately, an aide said.
Meanwhile, the top Roman Catholic clergyman in the Holy Land said the Israelis and Palestinians need new leaders if they hope to end their bloody conflict.
In an interview with the Associated Press at his office in Jerusalem's walled Old City, Latin Patriarch Michel Sabbah also said he does not believe Israel's separation barrier in the West Bank will bring security.
Sabbah, a Palestinian who was named patriarch in 1988, said he is not optimistic about a leadership change anytime soon, either on the Israeli or the Palestinian side.
"The land needs something new, a new vision, a new spiritual blood, a vision in which the leaders believe that both sides are capable of peace," Sabbah said.
Sharon suffered his latest legal setback Monday when the Supreme Court ordered his son to hand over potentially incriminating documents in a pair of corruption cases, including a bribery investigation involving the prime minister.
The decision came a day after Israel's chief prosecutor, Edna Arbel, recommended that the elder Sharon and his son be indicted in the 1999 bribery case, in which a real estate developer allegedly paid the Sharon family hundreds of thousands of dollars in exchange for help in promoting a tourism project.
The attorney general will make a final decision on a Sharon indictment in a month or two, reports CBS News Correspondent Robert Berger.
"The attorney general is independent, but he has really to have a very good reason why not to indict, said legal analyst Ze'ev Segal. The recommendation of the chief prosecutor "bears ... a heavy weight."
"If the attorney general will decide to indict the prime minister, the prime minister has to resign," said infrastructure minister Yosef Paritzky, a moderate.
Opposition legislator Yossi Sarid said he asked Sharon in a closed parliamentary hearing to suspend himself while the investigation is pending. Sarid quoted Sharon as telling him: "I am functioning as I should."
The investigations also have weakened Sharon's standing in his own Likud Party, throwing into doubt his plan to withdraw from most of the Gaza Strip and isolated West Bank settlements. Sharon has said he would go ahead if peace making with the Palestinian remains stalled.
Deputy Prime Minister Ehud Olmert, a close ally of the prime minister, told Israel Radio on Monday that Sharon will not be deterred.
"I am convinced that disengagement plan will advance and in the end will be carried out. The prime minister is determined to do this," Olmert said.
Sharon told parliament's Defense and Foreign Affairs Committee that he plans to seek Cabinet and parliamentary approval after returning from a trip to Washington next month, his spokesman, Assaf Shariv, said. Sharon is scheduled to meet President Bush on April 14.
Shariv did not say when the plan would be submitted. Binyamin Ben-Eliezer from the opposition Labor Party said Sharon told the committee the vote would be taken immediately after his return from the United States.
Sharon told the legislators if the plan is rejected, he would try to form a new government immediately. "If the parties leave the coalition, on the same day I will form a new government. There is no way I will go to an election," Shariv quoted Sharon as saying.
Sharon's aides have declined to comment on the corruption investigations. But privately, they say he has no plans to resign.
The prospect of an unprecedented indictment of an Israeli prime minister could have immediate political consequences — undermining Sharon's plan to pull out of Gaza, or conversely, pushing him to speed up the pullout to ward off legal action.
Even if Sharon survives an indictment, his government might not last. A coalition partner, the Shinui Party, has said it will leave the government if he is charged.
A collapse of the government would put the withdrawal plan in doubt. Sharon's most likely successor, former Prime Minister Benjamin Netanyahu, has shown little enthusiasm for pulling out of Gaza or the West Bank, areas captured in the 1967 Mideast war, with or without a peace deal.
In the meantime, Sharon faces fierce opposition to a Gaza pullback in his Cabinet — where hard-line ministers opposed to territorial concessions have considerable sway — and has failed to win U.S. guarantees that would make the plan more palatable to such critics.
Sharon's legal troubles have also caused concerns on the Palestinian side.
"We view this as an internal Israeli matter, but we worry that the Israeli government may attempt to divert the attention of the Israeli public from this corruption scandal to more Palestinian assassinations, incursions and bloodshed," said Cabinet minister Saeb Erekat.
Israel has stepped up its military activity in Gaza ahead of the possible pullout, wanting to portray a pullback as a victory over Palestinian militants. Last week,, the most senior Palestinian to be killed in three years of fighting.
The Palestinian Authority has given lukewarm support to the Gaza withdrawal plan, as long as it's a first step toward a larger Israeli pullback.