CAIRO - Members of Egyptian opposition socialist party Tagammu pressed the group's leader to withdraw from the second round of parliamentary elections they said were tainted by vote rigging, a party official said on Friday. The push comes after Egypt's two biggest opposition blocs said on Wednesday they would drop out of the poll before run-offs, an effort to diminish the legitimacy of the ruling National Democratic Party's (NDP) sweeping win in the first round. The NDP rejected charges it rigged the vote, saying it respected the law and the elections were fair. The run-off is scheduled for December 5. The government has said the vote was fair. "We want to withdraw because of the flagrant rigging by the government," Hany Ammar, a member of Tagammu's central committee, said by telephone from Alexandria. "The decision to continue in the elections does not represent the party or the majority of the party," he added. The liberal Wafd party and the country's biggest opposition group, the Muslim Brotherhood, lost heavily during Sunday's vote. Analysts expected the NDP to crush its Islamist opponents ahead of a presidential election next year. Ammar said party leaders staged demonstrations in Alexandria and Cairo on Friday and were planning a sit-in in front of Tagammu's Cairo headquarters on Saturday to protest the party's head's decision to enter the second round of elections. State newspaper al-Ahram's English-language website quoted Tagammu's leader Rifaat El-Said as saying the party "will wage a strong electoral battle and will not give the NDP the chance to take up all the seats." The party's secretary general was not available for comment on his cell phone. Tagammu held one seat in the outgoing parliament, and won one in the first round of Sunday's vote. It was set to contest six seats in the second round, Ammar said. Wafd, which controlled 12 seats in the outgoing parliament but won only two of 518 seats in the first round, confirmed it would drop out of the election despite members' protests against the decision. It was to contest nine seats in the second round. About 50 demonstrators against the boycott stormed Wafd's headquarters in central Cairo during a press conference on Thursday, shouting and waving banners in support of Wafd candidate Atef El Ashmawy. "We will participate, we will participate," they chanted. The High Elections Commission, a body of judges and parliamentary nominees, said the withdrawal of Wafd and the Brotherhood would not affect the electoral process. NDP has swept to routine victories for decades and is guaranteed a landslide once run-offs are held.