Defector General George Athor Deng said in his first public appearance in nine months that he would designate an assembly point for his troops in a step towards ending the war with the Sudan People's Liberation Army (SPLA).
The step, welcoming a peace initiative, corresponds with Sunday's much-awaited referendum on southern self-determination.
Deng vowed to respect the southern people's choice, whether it be secession or unity, and revealed he will be participating in its transitional government should it gain independence.
"It is due time for the south's suffering to end and work together for stability and development," Deng said.
South Sudan's government has considered the ceasefire signed two days ago in Juba with the Deng's affiliates the last step needed in the arrangement of an independent south and a pre-referendum gift to southerners. General Deng defected last April in protest over the south's election results and launched a military operation against the SPLA.
Vice-president of the government of South Sudan Riek Machar, who attended the signing of the ceasefire, asserted that the government wants harmony in the south, which is why President Salva Kiir Mayardit issued full pardons for all militants.
The pardons carried certain conditions, like enforcing a ceasefire.