The Sri Lanka Podujana Party and the SLFP are set to sign another Memorandum of Understanding on October 31, informed political sources said.
The SLFP has already signed two agreements with the SLPP and its candidate Gotabhaya Rajapaksa.
The third agreement will cover the formation of the Sri Lanka People's Freedom Alliance - the common alliance under which the two parties will contest upcoming elections.
It is learnt that they will use the Chair sysmbol for the common alliance. The same symbol was used by the SLFP-led alliance for all elections between 1994 and 2004.