Nearly half of the population of Libya people has been affected by violence and needs protection and some form of humanitarian aid, the United Nations says.
"Armed conflict and political instability has impacted over 3 million people across Libya," the Office for the Coordination of Humanitarian Affairs (OCHA) said in a report published on Thursday.
In a country of 6.3 million, "2.44 million people are in need of protection and some form of humanitarian assistance", it said.
The needy include people forced to flee their homes and those living in conflict-hit areas, as well as refugees, asylum-seekers and migrants, OCHA said.
Libya has had two parliaments and two governments since August 2014 when Islamist-backed militias seized Tripoli, prompting the internationally recognised government to take refuge in the far east of the country.
There have been clashes in major cities such as Tripoli, Misrata, Sirte, Benghazi and Derna along the coast and in the central oasis city of Sabha, OCHA said.
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 such as schools and warehouses, the report said.
"The displaced are particularly vulnerable due to limited coping capacities and loss of assets, particularly displaced women, children, the elderly and those who are impoverished," it said.
There have been widespread violations of international humanitarian and human rights law by all parties to the conflict, including against women and children, the UN agency said.
Major shortages of essential medicines and a debilitated health care system have led to an rise in serious illnesses and disease, it said.
"An estimated 250,000 refugees, asylum-seekers and migrants in Libya are facing significant protection concerns, with their status making them particularly vulnerable to abuse, marginalisation and exploitation," it added.
Libya has for years been a stepping stone for migrants seeking to travel to Europe, and people smugglers have exploited the chaos since Libya's 2011 revolution to boost their lucrative trade.
The armed conflict has also led to a decrease in school enrolment rates -- by 17 percent for girls and 21 percent for boys, said OCHA, especially in second city Benghazi where last month the army launched an offensive against rebel groups.