German Foreign Minister Heiko Maas had expressed hope during a visit to Libya at the end of October that the summit would take place this year.
Libya has descended into chaos since the overthrow in 2011 of its long-time ruler Moamer Gaddafi. Two governments are competing for power, numerous militias are fighting for influence and its capital Tripoli is contested.
Germany has been trying to mediate in the conflict since September, in hopes of avoiding a proxy war like in Syria. It wants to start by halting arms deliveries to the country.
Four preparatory meetings have already taken place as part of the mediation efforts, including one last week.
The goal is to have the five veto holders on the UN Security Council - the United States, Russia, China, Britain and France - meet with the regional powers involved in the conflict. They include the United Arab Emirates, Egypt and Turkey.
All three of those countries have been accused of delivering weapons to Libya.
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