The leaders say they have gathered solid evidence showing that the electoral process was manipulated to favour candidates allied to the ruling administration.
Speaking on Sunday during a service at AIC Mukuni Church in Machakos County, Wiper Party leader Kalonzo Musyoka accused the state of influencing the outcome of both by-elections.
He said the coalition has compiled detailed information which they believe will prove that the final results were altered.
Kalonzo told the congregation that President William Ruto was fully aware that UDA did not genuinely win either contest.
According to him, the opposition has evidence showing that the will of the people was undermined.
“William Ruto knows that UDA did not win in Mbeere and UDA did not win in Malava,” he said.
“We have evidence… direct interference.”
He further claimed that during the tallying of votes, some security officers faced pressure from senior government officials who wanted to influence the counting process.
Kalonzo alleged that certain leaders interfered with the ballot totals to tilt the final numbers in favour of the ruling party’s candidates.
He described the events as part of a wider, well-organized attempt to predetermine the outcome of the elections.
According to the opposition leader, the tallying process in both constituencies did not follow the expected procedures.
He insisted that the figures were manipulated and that the integrity of the by-elections was compromised.
“There was no vote tallying,” he said.
“We are going to have a very clear, strong petition.”