The government's talks in Havana with members of the Revolutionary Armed Forces of Colombia are aimed at ending 50 years of conflict, Colombia Reports reported.
Chief government negotiator Humberto de la Calle said his delegation had "all the will to advance" but the process "could not be prolonged indefinitely in time."
The government set November 2013 as the deadline for peace negotiations, but said it hoped a deal could be struck on agrarian reform before Easter.
FARC negotiators have voiced doubt about the deadline, Colombia Reports said.
"We cannot allow ... the electoral hurry of the [government to go] above the interests of all the Colombians," FARC negotiators said in statement. "Putting a deadline is not only unrealistic, it is a criminal behavior."