Prime Minister Ehud Olmert and Defense Minister Amir Peretz, who clashed last week over Peretz's conversation with Palestinian Authority Chairman Mahmoud Abbas, will wage a new battle this week over the vacant Social Affairs portfolio, a source close to Peretz said on Saturday night. Peretz, who wants to regain his image as a social activist ahead of the May Labor primary, told the party's executive committee on Thursday that he would not give up the fight for the portfolio. He said Olmert promised him that Labor would receive the ministry, a charge Olmert vigorously denies. "I agreed with the prime minister that if within a month, United Torah Judaism does not enter the coalition, we would receive the Social Affairs portfolio in return for another," Peretz told the crowd. "I promise that next week I will demand the portfolio from the prime minister and decide who will be the Labor minister who will fill the post." A source close to Peretz said he intended to "make a big issue" out of Olmert's failure to appoint a social affairs minister. The source said he "had no doubt that this would be the issue of the week." One candidate sure to receive consideration for the post if Labor receives it is Labor faction chairman Yoram Marciano, a native of Lod who was elected to a slot on Labor's candidates list representing poor neighborhoods. Marciano, who was Peretz's sole defender throughout last week's crisis, said the portfolio should go to someone with expertise in social affairs. Marciano said he expected Labor to fight hard for its interests ahead of Knesset votes next month on the final readings of the 2007 state budget. He said Labor was willing to leave the coalition if its demands on the budget were not accepted. Peretz convened his advisers late Thursday in the office of businessman Benny Gaon and told them he intended to "fight until the end" to remain defense minister. He said the only way he would leave the post would be if the Winograd Commission investigating the war in Lebanon demanded it or if Labor left the coalition. Leaving the coalition over socioeconomic issues could boost Peretz's sagging reelection campaign and allow him to take revenge against Labor ministers who have tried to pressure him to leave the Defense Ministry. In the meeting with his advisers, he accused Agriculture Minister Shalom Simhon, National Infrastructures Minister Binyamin Ben-Eliezer and Tourism Minister Isaac Herzog of being more loyal to Olmert than to him. Besides Marciano, the meeting was attended by Education Minister Yuli Tamir, Deputy Defense Minister Ephraim Sneh, MK Shelly Yacimovich, Jewish Agency Treasurer Hagai Merom and Gaon. The advisers recommended to Peretz that he not bother fighting for the Social Affairs portfolio because it was a battle he could not win. UTJ leader Ya'acov Litzman said there had been no progress with Kadima on his party joining the coalition and that he did not expect progress this week. He said he was not impressed by Peretz setting this week as a deadline for his party to join. "I have heard an ultimatum every week since this Knesset was elected so I am used to living with ultimatums," Litzman said. "There haven't been any negotiations and there won't be negotiations. I think Olmert needs us to stabilize his coalition, and if he wants to talk, he knows my address." Former deputy social affairs minister Avraham Ravitz of UTJ added that talks with his party had never reached the stage of practical dialogue. "There hasn't been a meeting with people who had the authority to negotiate, accept and sign," Ravitz said. "Litzman hasn't made it any easier. He is a problem and he is not ready to compromise." Assuming Labor does not receive the Social Affairs portfolio, Peretz would have to appoint a new science and technology minister to replace Ophir Paz-Pines, who quit on October 30. Peretz hopes to use the vacancy to help his chances of getting reelected. To that end, he offered the post over the weekend to United Kibbutz Movement secretary-general Ze'ev Shore, the strongman of Labor's most important sector. Shore turned down the offer because he fears that Labor will not remain in the coalition for more than a few months and he did not want to risk losing his current job over a temporary promotion.