Sources said an important person could announce joining the PSP.
In an interaction with journalists, Kamal said MQM should get ready for another by-election.
Mutahidda Qaumi Movement has also called a press conference to be addressed by senior party leader Nadeem Nusrat.
Opposition Leader in the Sindh Assembly and MQM lawmaker Khwaja Izharul Hasan said ‘those claiming to take wickets of their rivals should now protect their own wickets.’
Several MQM dissidents including Dr Sagheer Ahmed, Raza Haroon, Waseem Aftab have joined the PSP founded by Kamal and Anees Qaimkhani.