Marxist FARC rebels and representatives from Colombia's government sat down together on Tuesday for the first time in more than a month, tying up loose ends as they embark on a new round of peace talks.

The meeting is the first between the two sides since the re-election last month of President Juan Manuel Santos, which gave a big push to the negotiations.

Officials told AFP that a few unresolved matters must be attended to before the two sides can take up the thorny issue of compensating victims of the half century long conflict.

"There are one or two meetings to wrap up unresolved things before starting on the issue of the victims," a source in the government's delegation told AFP.

"It is not exactly a new round of talks, rather a meeting of the parties to deal with some issues," said Andres Paris, a member of the delegation representing the Revolutionary Armed Forces of Colombia, or FARC, at the negotiations in the Cuban capital.

Participants said one of the key issues under discussion dealt with establishing ground rules for allowing victims of the violence to sit in on the talks.

"We want to discuss the time, the procedure, and the date that this can begin taking place," said lead government negotiator, Humberto De la Calle.

The preliminary talks are to last just a couple of days, rather than the usual 11-day-long round, to allow the participants to "fine tune" the procedures with respect to the participation of victims.

Agreement between the two sides has been reached already on three agenda points: rural development; the rebels' reintegration into the political process; and illegal drugs.

In addition to the question of victims' compensation, there are two more issues to be taken up: the laying down of weapons by the FARC, and determining whether an eventual comprehensive peace agreement should be put to a national referendum, as the government insists.

Talks on ending Latin America's longest running armed conflict, which has raged since the FARC's founding in 1964, have been under way in Havana since November 2012.

A center-right leader, Santos had staked his presidency on a negotiated peace with the FARC, Latin America's oldest and largest insurgency, with about 8,000 men under arms.