A Swiss delegation has visited Libya, the foreign ministry confirmed on Monday evening, without giving further information.
The delegation was not accompanied by the two Swiss businessmen, who have been held in Libya for more than one year.
Authorities said the trip was part of an agreement to normalise relations between Bern and Tripoli.
It was led by the state secretary at the Swiss foreign ministry, Michael Ambühl, and included officials from the finance ministry. Swiss President Hans-Rudolf Merz holds the finance portfolio.
Tuesday marks the end of a 60-day deadline for normalising relations. The date was set in an accord signed on August 20 by the two countries during a visit to Tripoli by Merz.
The Swiss delegation had reportedly left Libya by Monday evening.
The two countries have been at odds since Geneva police arrested Libyan leader Moammar Gaddafi's son Hannibal in July 2008. Libya removed billions from Swiss bank accounts, cut air links and revoked exit visas for two Swiss nationals.
Merz travelled to the country in August in an attempt to defuse the conflict. He apologised to Libya and the two sides agreed to have a solution by October 20.
The fate of the two Swiss nationals is unknown.
In an interview published on Saturday, Foreign Minister Micheline Calmy-Rey said attempts at third-party mediation had failed.
Merz said on Saturday he was "optimistic".
swissinfo.ch and agencies