The National Super Alliance (Nasa) has disputed preliminary presidential results as released by the electoral commission.
Presidential candidate Raila Odinga early Wednesday termed the outcome that saw him trail Uhuru Kenyatta by more than one million votes as "sham, fictitious and fake".
Mr Odinga said the results were the "work of a computer" and did not reflect the will of voters, a claim denied by the Independent Electoral and Boundaries Commission.
He asked IEBC to provide forms 34A and 34B to help verify the outcome.
He spoke moments after his chief agent Musalia Mudavadi and Nasa lawyer James Orengo made similar claims at Bomas of Kenya.
Mr Orengo said forms 34A and 34B should be the basis of the results but the commission was just keying in results without scanning the forms as required.
"It beats common sense for those results to be admitted. The results announced at the polling station are final," he said.
Mr Orengo said the commission had assured them that the forms would be available in their mails, if they needed them.
"We were given that guarantee more than an hour ago, that we will get the transmitted forms.
"But as we speak now, those forms have not been availed to us. If one wants to know what a fraud is; this is one," he said.
They insisted on the forms signed by agents at the constituency level.
Mr Orengo said what the IEBC was doing is a replica of 2007 and 2013, where the electoral body transmitted results without a basis for verification.
He said IEBC can wait for forms from the polling stations, if the scanned ones are not available.
"It is disturbing that after a long process, the commission will commit such a fraud. Kenyans should ignore those results.
"According to us, the results are null and void because they are not backed by any evidence. We will not keep quiet but reject them," he said.
But CEO Ezra Chiloba said the results being displayed at the national tallying centre have been transmitted from the constituencies after scanning Form 34B.
"We urge Kenyans to be patient as we continue to tallying and relaying the results," he said.
Reported by John Ngirachu, Sam Kiplagat, Valentine Obara, Ibrahim Oruko, Samwel Owino, Patrick Langat and Dennis Onsongo.