"The president renewed his support for the internationally-recognised government and urged an end to unlawful attacks by Haftar's forces," the presidency said in a statement.
Erdogan met with Libyan Prime Minister Fayez al-Sarraj in Istanbul earlier on Friday.
The Turkish leader told Sarraj his Libyan Government of National Accord had Ankara's support in its bid to ensure Libya's peace and stability, the presidency added.
Haftar's forces, which hold much of eastern and southern Libya, launched an offensive in early April to seize the capital from the government.
Last month Haftar ordered his forces to target Turkish companies and arrest Turkish nationals after he lost a major town to forces backing Sarraj's government.
Six Turkish sailors were briefly held by the strongman's forces but were released earlier this week after Turkey vowed to retaliate if they were not freed.
Turkey's interest in Libya goes back to its Ottoman past as the country was part of the empire until 1912 when Italy then conquered the north African country.
Libya has been mired in chaos as multiple militias vied for power after a NATO-backed uprising resulted in dictator Moamer Kadhafi's death in 2011.
Haftar was a retired general who took part in the uprising but in May 2014 he launched his assault to purge the country of Islamists whom he says are "terrorists".