"The war is over," said Ivan Marquez at a national conference of the FARC to vote on the deal and relaunch the group as a political party.
"The guerrillas... have given their unanimous backing to the final accord," he said.
Marquez, who led the FARC's delegation at nearly four years of peace talks in Cuba, added a reference to one of Colombia's most famous sons, the Nobel prize-winning writer Gabriel Garcia Marquez.
"Tell Mauricio Babilonia he can release the yellow butterflies," he said, a reference to a character in the master of magical realism's "One Hundred Years of Solitude" who is so love-struck that a cloud of yellow butterflies follows him wherever he goes.
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President Juan Manuel Santos and FARC leader Rodrigo Londono -- better known by his nom de guerre, Timoleon "Timochenko" Jimenez -- will now sign the accord Monday in the Caribbean coast city of Cartagena.
The FARC, a Marxist guerrilla group, launched its war on the Colombian government in 1964, in the aftermath of a brutally repressed peasant uprising.
Over the decades, the conflict has drawn in several leftist rebel groups, right-wing paramilitaries and drug gangs, leaving a legacy of death and destruction: more than 260,000 people killed, 45,000 missing and 6.9 million forced to flee their homes.
The FARC is also due to announce details on its new life as a political party as its conference wraps up Friday in El Diamante, a remote site deep in its traditional stronghold in southeastern Colombia.
