He is responding to a remark by minister Lakshman Kiriella in Galagedara two days ago that the meeting could divide the SLFP.
Although MP Yapa says the SLFP has not been invited to attend the meeting, MEP leader Dinesh Gunawardena says invitations have been sent to all affiliate parties of the UPFA.
He says the choice of the SLFPers will become clear tomorrow.
However, a group of SLFP politicians has decided, going against a party decision, to take part in the meeting.
Meanwhile, the SLFP Bala Mandalaya in Biyagama that met today unanimously adopted a proposal that former president Mahinda Rajapaksa should be the prime ministerial candidate at the upcoming general election.
Western provincial councillor Gunasiri Jayanath moved the proposal at the meeting, also attended by new national organizer of the party Susil Premajayantha.