NAIROBI, Kenya — Kenya’s electoral commission said Wednesday that it would go ahead with a repeat of the recent presidential election, even though one of the main candidates has said he is withdrawing from the race because he does not believe it would be free and fair.

The commission said it was opening up the new vote, scheduled for Oct. 26, to other candidates who had run in the initial election in August. But with the opposition leader Raila Odinga declaring his withdrawal, President Uhuru Kenyatta is likely to win easily in a contest against six other candidates who failed to win much support in the earlier election.

Mr. Odinga has contended that the Supreme Court, not the electoral commission, should be in charge of overseeing the election.

In a statement, the commission said that “candidates for the fresh presidential election scheduled for 26th of October shall include all eight candidates who participated in the 8th August presidential election.” It added that Mr. Odinga had not formally withdrawn from the election.