Mvita MP Abdulswamad Shariff has said Jubilee used Sh300 million to bribe voters during the Malindi by-election.
He alleged the money was "part of the unaccounted cash from the Eurobond, NYS and the Youth Enterprise Development Fund".
"They used Sh300 million to buy 9,000 votes," Shariff said.
But Ganze MP Peter Shehe, allied to Jubilee, denied the allegations.
"That is not true," he told the Star on the phone on Saturday.
Speaking at a rally in Mombasa on Friday, the Mvita legislator said he will make sure Jubilee is held accountable for lost funds.
"I am a member of the Public Investments Committee that investigates lost funds and I will use my position to get answers from implicated officials allied to the government," Shariff said.
"I will punish you. I will make sure you have paid the money to the last coin."
Mwea MP Peter Gitau and his Kabete counterpart Ferdinand Waititu of Jubilee were briefly arrested for allegedly bribing voters, while OD's Philip Etale was released on Sh30,000 cash bail for illegally handling election material.