UNITED NATIONS, United States (AFP) - US Secretary of State John Kerry urged Libya's rival factions on Friday to move forward with a UN-brokered peace deal and agree on appointments to a new unity government in the coming days.

Kerry spoke at a UN meeting called to push all sides to come up with a new power-sharing authority that can start pulling the north African country out of the chaos that has spread since the 2011 fall of Moamer Kadhafi.

"There is no time to waste," Kerry said, urging all sides to urgently agree on candidates for the new government.

"We hope that the process can be completed within a very small number of days," he said.

The United Nations has been piling pressure on Libyan factions to take the final step and make the appointments after months of difficult negotiations and missed deadlines.

A unity government in Libya is seen as the best chance to tackle migrant-smuggling from Libyan territory across the Mediterranean and the rise of the Islamic State group.

UN envoy Bernardino Leon has said that a deal should be reached before October 20, when the mandate of the internationally-recognized parliament expires.

Libya has had two parliaments and two governments since August 2014 when Islamist-backed militias seized Tripoli, prompting the internationally recognized government to take refuge in the far east of the country.

Since last summer, some 435,000 people have been forced to flee their homes, of whom 100,000 now live in outdoor camps or abandoned buildings, the UN says.

Kerry stressed that energy-rich Libya could generate prosperity if it has a stable government.

"It should be possible with those level of resources and that size of a country for every person to have a piece of the pie," he argued.

UN Secretary-General Ban Ki-moon warned that those who refuse to take part in the peace effort and "remain outside this framework will be responsible for the consequences and suffering that will ensue."