The chief opposition leader is to return to South Sudan from a two-year self-imposed exile on Saturday following a presidential pardon in mid October.
SPLM-DC Acting Secretary-General Deng Bior Deng said on Thursday that the return of Lam Akol Ajawin would make a difference in the constitutional development process, Bakhita Radio reported.
He added that the country will move forward if the different parties work together to solve pressing issues.
Mr Deng said the absence of Dr Akol was not welcome news by the people of South Sudan.
He said the return of the SPLM-DC leader puts an end to a number of accusations labelled against the party and its leader.
Mr Deng explained that the SPLM-DC is an opposition party, not an enemy.
He added that the SPLM-DC was not against President Salva Kiir Mayardit but opposed some SPLM policies.
Lam Akol left South Sudan in December 2011.