The United Nations said it will launch talks on Wednesday between warring Libyan factions, even though one of the delegations has delayed its decision on attending a process aimed at averting wider conflict in the oil-exporting state.
Western governments hope talks in Geneva this week would ease a crisis in Libya where two rival governments and their forces are vying for control, three years after the fall of Moammar Gadhafi.
"The United Nations Support Mission in Libya [UNSMIL] has confirmed that the meeting of Libyan parties will start tomorrow Wednesday 14 January 2015 in the afternoon at the Palais des Nations in Geneva," a U.N. statement said.
Bernardino Leon, Special Representative of the Secretary-General for Libya and Head of UNSMIL, will give a press conference before talks start, it said, adding that the list of participants would follow.
The internationally-recognized government of Prime Minister Abdullah al-Thinni has been based out of eastern Libya since the summer after a faction called Libya Dawn took over Tripoli and set up its self-declared government and legislature.
Tripoli-based forces said their legislature had postponed a decision over joining the Geneva talks until Sunday because of concerns about how the negotiations were organized.
"We do not reject dialogue, but we believe that the U.N. rushed to determine the date of the dialogue and its mechanisms," said Omar Hmaidan, spokesman for the Tripoli legislature on Monday. "We have decided to postpone the vote to participate or not to next Sunday."
The decision from Tripoli appeared to push back the chance of any meaningful talks between the two sides.
A delegation from the elected House of Representatives, representing Thinni's government, was already in Tunisia waiting to fly to Geneva, according to a parliament representative.
The European Union had called the Geneva talks the last chance for Libya, with Western governments increasingly concerned over the instability spilling into a broader civil war just across the Mediterranean from mainland Europe.
Diplomats expected the Geneva talks to be initial, indirect negotiations over U.N. objectives for a unity government and an end to hostilities rather than any swift resolution.
The conflict involves two broad coalitions of political rivals and their allied brigades of former rebels who once fought side by side against Gadhafi but have since turned against each other.
Thinni's government and forces are broadly anti-Islamist, allied to former rebel militias from the town of Zintan, and a former Gadhafi army general, Khalifa Haftar, who Thinni has incorporated into his government's armed forces.
Libya Dawn forces are mostly allied to the rival city of Misrata, but also include some Islamist-leaning former rebels and politicians. They deny charges they are linked to radical Islamist groups.
The new rulers in the capital are not recognized by the United Nations and world powers, but have taken over ministries, oil facilities, airports and much of western and central Libya.
Libya's oil production has slumped to around 300,000 barrels per day as petroleum revenues increasingly become the focus of fighting. Two major eastern oil ports and their fields are still closed after clashes for control of the terminals.