Colombia's Senate on Tuesday began debating the government's controversial revised peace deal to end a half-century conflict with leftist FARC rebels.

Last month voters surprisingly snubbed an earlier version of the accord in a referendum.

Critics said it went too easy on the rebels, who have been waging what is now Latin America's last major insurgency.

Now the government hopes to implement a revised accord through its majority in the legislature.

Senate president Mauricio Lizcano opened the session in the upper house of the legislature, which will debate the accord before voting and passing it to the lower house.

The government hopes to push through the deal this week.

The government's chief negotiator at the peace talks, Humberto de la Calle, was due to speak, followed by other defenders and opponents of the deal and finally senators.

President Juan Manuel Santos insists the new proposal is stronger and takes into account changes demanded by his political opponents.

However his chief rival, ex-president Alvaro Uribe, has rejected the revised deal.

Uribe has insisted, for instance, that FARC leaders should not be allowed to run for office while still serving sentences for atrocities.

He demands any new accord be passed by referendum.

The conflict has killed at least 260,000 people and displaced seven million, according to authorities.

Before starting the session, senators held a minute of silence for the victims of a charter plane that crashed in the mountains of northwestern Colombia on Monday with a Brazilian football team on board.