The Orange Democratic Movement (ODM) party has raised alarm over the Bonchari by-election happening on Tuesday.
ODM Secretary-General Edwin Sifuna on Monday claimed that there is a plan to rig the election.
Speaking after inspecting election materials at the Bonchari tallying centre, the SG claimed that there were marked ballot papers at a senior politician's home in Kisii town.
Without naming the suspected politician, SG Sifuna assured that any attempt to sneak those ballot papers to any polling station will be resisted with full force.
"We continue to insist that as stakeholders in this election for a free and fair election... that is the very minimum set out in the law," SG Sifuna stated.
The Orange party has fielded former Energy and Petroleum Regulatory Authority (EPRA) CEO Pavel Oimeke in the contest for the MP's seat.