Nasa politicians on Monday took their "no reforms, no election" campaign to Gusiiland, asking voters to stay at home on Thursday -- the day of the presidential repeat election.
Leader Raila Odinga accused the Jubilee administration of having tried to influence former electoral agency commissioner Roselyn Akombe before she quit.
Addressing public rallies in Nyamira and Kisii counties, Mr Odinga told residents not to take part in what he termed "a shambolic election".
By voting, they would betray the sacrifices made by their son Chief Justice David Maraga and daughter Akombe on the principle of credible elections, he said.
"Let us not shame our heroes and heroines Maraga and Akombe for standing up for justice. Do not take part in the October 26 fresh presidential poll," he told residents in Kijauri, Keroka, Keumbu and at Gusii stadium.
Dr Akombe resigned from the Independent Electoral and Boundaries Commission last week and flew to New York, where she talked of threats to her life and deep divisions within the commission, making it impossible for it to run a credible election.
Justice Maraga, who oversaw the first ever nullification of a presidential vote in Africa, has in the past distanced himself from political pronouncements from both Jubilee and Nasa.
Mr Odinga, accompanied by co-principals Moses Wetang'ula and Musalia Mudavadi, said nothing could convince them to take part in the poll -- not even the three-week leave by IEBC chief executive Ezra Chiloba, who last week temporarily removed himself from the commission over the election period.
"We know Chiloba has already set the stage for rigging. We are not fools!" he said.
Co-principal Kalonzo Musyoka addressed the crowd on phone from Germany, saying Kisii was a land of heroes and heroines.
"I urge you to boycott the October 26 election," he said.
Mr Mudavadi told Dr Matiang'i to tell Kenyans who were indiscriminately shooting innocents Kenyans during Nasa protests, if they were not policemen.
Reported by Ruth Mbula, Henry Nyarora and Elgar Machuka