Former Labor Party chairman MK Shimon Peres announced last night that he is leaving the party to which he has belonged for 46 years and will move his support to Prime Minister Ariel Sharon's Kadima party.

"My party activities have reached an end. In my opinion, the appropriate person to head the coalition that will bring peace is Arik Sharon," Peres said in a trembling voice at a press conference. "I held talks with him, and I'm convinced that he's determined to continue the peace process. I was informed that he is open to creative ideas to attain peace and security. I have decided to support him in the elections and to cooperate with him in attaining these goals."

Peres has been assured a ministerial portfolio if Sharon wins the March 28 election, but will not be on the Kadima list. Sharon associates said yesterday there was no doubt that Peres is an important figure who would become an integral part of Kadima's leadership.

Peres, who lost the race for Labor chairman to Amir Peretz three weeks ago, said the decision to leave the party was quite hard.

"This is a difficult day for me in which I ask myself: What is the central issue standing before the State of Israel now and in the coming years? I have no doubt that it is the unavoidable combination of peace and diplomatic advances. I ask myself how I can contribute in the coming years, and the answer is by advancing the peace process that will contribute to a thriving economy and social justice," he said.

"It was not easy, but I made the choice and decided."

Peres' Labor Party supporters held a separate press conference yesterday urging him to remain in the party. They presented a petition reading: "Those who admire and love you, who go with you and after you to fulfill your vision, come to you with an emotional request from the depth of the heart not to leave home."

Top Labor officials, meanwhile, accused Peres of abandoning the party.

"I'm sorry about Peres, who did so much for the country but will be remembered as someone who abandoned his home, which he led for dozens of years, in favor of an `instant career' party that no one knows where it came from or where it's going," said Labor MK Ophir Pines-Paz. He also criticized Peres for saying he was leaving the party for the sake of peace.

"The Labor Party is committed to peace more than any other, and Peres' attempt to use peace as an excuse is pathetic," he said.

Labor Party Secretary General MK Eitan Cabel said it was a sad day in which a leader who had received so much from the Labor Party abandoned it just as it appears to be full of new hope and on its way back to power.

MK Ran Cohen (Meretz-Yahad) said Peres' departure did not serve either the country or the cause of peace, but was meant to help him personally.

While Peres apparently will receive a cabinet portfolio in the event of a Sharon government, Peretz had refused to reserve the No. 2 slot for the veteran Laborite.

Likud politicians, meanwhile, said Peres' decision shows that Kadima is a left-wing party, with some predicting that the move would help win back Likud voters.

Likud faction chairman MK Gideon Sa'ar said the fact that Kadima has joined forces with Peres, "who symbolizes the Labor Party most of all, and is most identified with left-wing policies and the Oslo Accords," proves that Sharon's party is left wing, and that voting for it is like voting for Labor.

MK Benjamin Netanyahu, the front-running candidate for the Likud chairmanship, said "a second Labor Party has been established. Now it's more clear than ever that Kadima is the left - Dalia Itzik, [Haim] Ramon and this evening, Peres. This shows more clearly than anything that Likud voters are returning, and will return home, en masse to the right way and the warm home of the Likud."

"Whoever votes for Kadima gets Peres, Itzik and Ramon as a package deal," said Health Minister and Likud MK Dan Naveh. "This is the moment when Likud members will start to return home."