Colombia's constititutional court gave its approval on Monday for a popular referendum on a historic peace deal being negotiated with FARC rebels.

"There is a green light for us, the Colombian people, to approve the peace deal with our votes," President Juan Manuel Santos said.

The top court held more than eight hours of deliberations before giving its go-ahead to a government bill on the plebiscite, which has already been approved by Congress.

The Colombian government and the Marxist Revolutionary Armed Forces of Colombia (FARC) are in the final phase of four years of talks that it is hoped will result in a peace deal putting to an end a half-a-century of conflict.

The rebels last month signed a ceasefire and disarmament deal with the government, with the aim of becoming a political party.

The government said it hoped to move on to a full peace deal within weeks.

Alejo Vargas, an analyst at the National University's Center for Reflection and Monitoring of the Peace Dialogues, has said government supporters of the peace deal are in the majority. In a referendum, he estimated, "up to 70 percent would vote 'Yes.'"