Levan Gachechiladze, the leader of Georgia's United Opposition, said on May 23 that his bloc refused to enter parliament and called for protests on May 26, which is Georgia's Independence Day.
According to the Central Election Commission, Saakashvili's United National Movement won the May 21 elections with nearly 60 percent of the vote. The United Opposition bloc finished a distant second, with nearly 18 percent. The Christian Democratic Movement and the Labor Party also gained seats in the parliament.
The opposition has accused the authorities of gross electoral violations, including voting with forged identification and police intimidation.
Davit Gamkrelidze, one of the United Opposition leaders and the chairman of the New Rightists party, said the parliament he is boycotting would be a product of terror.
"I have no right to enter a parliament that is the product of illegality, terror, and an illicit government. I cannot become a member of a parliament that is illegitimate, unlawful, and which is a product of Soviet-style elections," Gamkrelidze said
RFE/RL's Georgian Service Director David Kakabadze said the boycott could widen, with a "high probability" that the Labor Party will join. The Christian Democratic Movement, however, has said it will not take part. Reports Of Violations
Election monitors have said the vote was marred by violations, but was an improvement over January's presidential vote.
A report from the International Election Monitoring Mission stated that "there were numerous allegations of intimidation, some of which could be verified."
Joao Sores, the head of the OSCE Parliamentary Assembly delegation, said the elections were not perfect, but substantial improvements had been made since January.
The U.S. State Department also said the elections were an improvement over the January vote.
Those elections, which were won by Saakashvili, were preceded by weeks of opposition protests. Saakashvili's government was accused of using heavy-handed tactics, after police used force to break up an opposition demonstration. Presidential Test
This week's parliamentary elections were seen by many as a test of Saakashvili's democratic credentials. After criticism of his government last year, the Georgian president pledged to run a more open government and work more closely with the opposition.
Analysts say that Saakashvili may now be able to push ahead with his reform agenda. If the opposition continues its boycott, Saakashvili's party will have virtually all the seats in parliament.
The chairman of the Central Election Commission, Levan Tarkhnishvili, told RFE/RL's Georgian Service that seats won by the United Opposition would not be redistributed to other parties. And on May 24, the commission said parliament will start working if two-thirds of all deputies participate. In the single-mandate vote, Saakashvili's party won 120 out of 150 seats, over the two-thirds mark.
NATO has said that the success of the polls would play a key part in the alliance deciding in December whether Georgia will be given a Membership Action Plan toward eventual membership.