In light of expectations that Hamas will gain a significant number of seats in the upcoming Palestinian Legislative Council elections, the prime minister's adviser Dov Weisglass is set on Sunday to head a study team to examine the impact of such a victory. Prime Minister's office spokesman Ra'anan Gissin said that Israel's policy with respect to Hamas remains firm. "Israel is not going to negotiate with a Palestinian government that is controlled by Hamas," Gissin told The Jerusalem Post. "We are discussing what is going to be the day after the elections, if they take place and if Hamas achieves a significant result," said Gissin. "We have to prepare for the worst possible scenario," he added. Prime Minister's office spokesman Asaf Shariv added the study would examine the meaning of Hamas winning a small percentage of seats in the PLC, versus a large one, and make policy recommendations. The study would then be given to the government, he said. Weisglass is also likely to discuss the matter with US Assistant Secretary of State David Welch who is expected to visit the region this week, said Shariv. Included in Weisglass' team is Foreign Ministry's director-general Ron Prosor, Maj.-Gen. (ret.) Amos Gilad, the head of the Defense Ministry's political desk and representatives from the IDF, the Shin Bet, the Prime Minister's office and the Justice Ministry, said Shariv. Hamas leader Mahmoud a-Zahar said last Thursday that he did not rule out the possibility that his movement would negotiate with Israel in the future. But Israeli officials have said that such discussions are not possible unless the group accepts Israel's existence as a state and renounces violence. Vice Premier Shimon Peres (Kadima) told Israel Radio Saturday that if Hamas led the PA, it would put the entire road map in question. "A Hamas takeover would endanger any aid offered to the Palestinians, since no country would provide financial or any other kind of aid to an authority headed by an armed organization of terrorists," he said. In a later interview with Channel 2, he added, "Unless Hamas, like (former Palestinian Authority Chairman Yasser) Arafat, announced that they will give up their arms, that is something else." Gissin told the Post he is fearful that Hamas could gain enough seats to become part of the government. A public opinion poll from last week showed Hamas winning 31.4 percent of the vote. If Hamas received 40% of the vote, said Gissin, "it would constitute a major victory" that could put Hamas in the government. It's a move that would make it impossible for Israel to conduct negotiations with the Palestinian Authority, warned Gissin. "Hamas has never accepted the road map, let alone Israel's right to exist. Hamas is a terrorist organization and it continues to engage in terrorist activity," he said. US and European politicians have also voice concerned with respect to Hamas. Earlier this month, EU foreign policy chief Javier Solana warned that EU funding to the PA would be jeopardized if the PA government includes a faction that won't renounce violence and recognize Israel's right to exist. Similarly, earlier this month the US House of Representatives passed a resolution threatening to cut off future financial aid to the PA on the same grounds. In a sharply worded statement, on Wednesday, the Quartet, which consists of the US, EU, Russia and the United Nations, issued a statement that said, "a future Palestinian Authority Cabinet should include no member who has not committed to the principles of Israel's right to exist in peace and security and an unequivocal end to violence and terrorism." Khaled Abu Toameh and Hilary Leila Krieger contributed to this report.