He has already given the necessary instructions to general secretary of the party Duminda Dissanayake.
Ex-president Chandrika Kumaratunga too, has agreed to this proposition.
Last Wednesday, the president warned that he would never let go of Rajapaksa if he supported a new party and opposed the SLFP.
He told SLFP local government members that he had done no harm to the Rajapaksas, who had paved the way for his leaving the party.
Mr. Sirisena said he knew everything about the Rajapaksa, and that the ex-president would not be allowed the stay in the country if the people got to know all about him.