Ghassan Salame said in a video briefing to the Security Council that the U.N. will announce the date and place of the National Conference once Libyan representatives agree on "the essential ingredients for a new consensus on a national agenda."
"We are working night and day to pull together these various elements to ensure the most productive event," he said.
Salame stressed that only Libyans can plot a way out of the political deadlock in the country which "has been underpinned by a complex web of narrow interests, a broken legal framework, and the pillaging of Libya's great wealth."
Salame cited some progress in Libya in recent months to stabilize the country and improve living conditions including a September cease-fire which has generally brought calm to the capital, Tripoli, but has been broken including on Dec. 25 with an attack by Islamic State extremists on the Ministry of Foreign Affairs and two days ago with renewed clashes.
On another positive note, U.N. envoy said the economy has continued to stabilize, and the black-market price of the Libyan Dinar against the U.S. dollar "has collapsed" as a result of measures announced last September.
"Inflation has steadied and commodity prices have dropped substantially," Salame said. "In a country that imports a huge part of its needs in hard currency, prices are down sometimes by 40 percent."
But the U.N. envoy said: "there is an imperative to improve security across the country," citing terrorist strikes in various towns and cities
Salame said he heard first-hand about "the wanton brutality" of Islamic State militants, foreign mercenaries and criminals who prey on citizens and migrants during a trip a few days ago to southern Libya, the first by a U.N. envoy since 2012.
"The south remains Libya's vulnerable heart, encompassing almost 1 million square kilometers of land," he said. "The source of much of the nation's natural wealth, through its water and oil, has been woefully neglected."
Salame said oil production had topped one million barrels a day, "driving much needed revenue into the treasury," but disturbances at southern oil fields over the lack of services in the region have recently reduced production.
Calling recent gains "fragile and reversible," he stressed that "concerted national leadership" is key to uniting the country and improving the economy.
"I beseech the members of the various Libyan institutions to see the National Conference as a patriotic concern that transcends partisan and personal interests."
Salame warned of "spoilers" who seek to undermine the conference, "particularly individuals hoping to delay elections so they may remain in their (parliamentary) seats."
"Without the concerted support of the international community, spoilers will sabotage the political process and undo any progress made," he said.