Confusion marred ODM repeat polls in Kisumu Central early Tuesday morning.
There were delays in the distribution of polling materials at a number of polling stations.
This, in turn, affected voting, which was to start at 6am.
Voting kicked off at Kosawo Primary School in Manyatta shortly after 9am.
Some pupils were turned away from their schools as they are being used as polling centres.
Kisumu County Director of Education Sabina Aroni said school heads were directed to ensure sites were closed to learning today to avoid a clash of events.
There was also confusion at the Jomo Kenyatta Sports Ground, which is being used as a polling station and also as a KDF recruitment centre.
The repeat elections were ordered by the High Court on Friday after a dispute arising from the April 25 botched party primaries was lodged.
Justice Francis Tuiyot overturned the Political Parties Disputes Tribunal's decision ordering the party to give incumbent Ken Obura the nomination certificate.
He ruled that the party conduct repeat nominations after former TNA secretary-general Onyango Oloo, who defected to ODM in January, contested Mr Obura’s win.