ODM party leader Raila Odinga has told former party members who defected to Jubilee to return to the party.
Raila said Jubilee's future is uncertain since the ruling coalition has no better agenda for the country.
He said ODM's doors will remain open to former party members to return to the country's largest party.
"We are ready to receive you," he said at Kisumu's Jomo Kenyatta Sports Grounds during a voter registration inspection exercise.
"We are committed to ensuring the party conducts free, fair and transparent party primaries. ODM is your home. Return home."
He spoke a day after former TNA Secretary General Onyango Oloo defected from Jubilee party and returned to ODM.
Mr Oloo played an instrumental role in President Uhuru Kenyatta's election in 2013 as he was among the few Jubilee members who risked campaigning for Mr Uhuru in Luo Nyanza.
Oloo claimed there was favouritism in Jubilee Party and that the political outfit did not give him the opportunity to run the party independently as Secretary General.
There are also reports that Nairobi Senator Mike Sonko, former TNA Chairman Johnson Sakaja, former Starehe MP Margaret Wanjiru and Mathare MP Stephen Kariuki are contemplating returning to the Orange party.
The four, since 2013, have closely been working with Jubilee.
Raila began a nationwide tour on Monday to sensitize Kenyans to turn out in large numbers register as voters ahead of the August general elections.