Kenya's electoral commission has warned the opposition that its claims of victory for its presidential candidate, Raila Odinga, could be deemed illegal.
The opposition has published its own figures, putting Mr Odinga ahead of incumbent President Uhuru Kenyatta.
This contrasts with provisional electronic results giving Mr Kenyatta a clear lead in Tuesday's poll.
Electoral commission chairman Wafula Chebukati told the BBC it was the only body legally allowed to count votes.
He accused the opposition coalition of basic mathematical errors.
International observers have described the election as free and fair.
However, many fear a repeat of the violence after the disputed election 10 years ago when more than 1,100 Kenyans died and 600,000 were displaced.
On Thursday, scores of people took to the streets of Mathare, a slum in the capital Nairobi, shouting "Uhuru must go".
Mr Chebukati said that the documents containing the real results were still being sent from constituencies to their national tallying centre.
Mr Odinga has said the IT system of the electoral commission had been hacked and Kenya was witnessing the worst "voter theft" in its history.
But the commission said that while there had been an attempt to hack its system, it had failed.
The final outcome should be announced later on Friday.