The UN envoy for Libya arrived in Tripoli Friday to encourage the administration there to commit to a national unity government aimed at ending years of violence in the country.

Martin Kobler, on a desperate diplomatic push to get two separate administrations to sign a power-sharing agreement, met Thursday with representatives of Libya's internationally recognised government near its eastern headquarters.

"More discussions in Tripoli -- I invite all to take responsibility for Libya's future, take responsibility for next generations," Kobler tweeted after meeting with head of the rival parliament in Tripoli, Nouri Abusahmein.

Libya has been in chaos since the 2011 ouster of longtime dictator Muammar Gaddafi and now has two governments and parliaments.

Jihadist outfits such as ISIS group have taken advantage of the lawlessness to make gains along the coastline, and the UN estimates that 435,000 people have been forced from their homes due to fighting.

On December 17, under UN guidance, envoys from both sides and a number of independent political figures signed a deal to unify the government.

Around 80 of 188 lawmakers from Libya's internationally recognised parliament and 50 of 136 members of the rival Tripoli-based General National Congress signed the deal.

It calls for a 17-member government, headed by businessman Fayez el-Sarraj as premier, based in Tripoli.

But analysts have cast doubt on the viability of a deal that would seek to bring together two parliaments controlled by hardliners.