Recep Tayyip Erdogan held talks with Prime Minister of Libya's Government of National Accord, Fayez Al Sarraj, in Istanbul on Sunday, days after he said he was ready to send troops into Libya if asked.
The closed-door meeting, which was not on Mr Erdogan's official agenda, took place in Istanbul's Ottoman-era Dolmabahce Palace, the Turkish presidency said.
In the previous meeting between the two men in Istanbul on November 27, they agreed on a deal for security and military co-operation, and maritime jurisdiction.
The agreement came despite calls from the Arab League, which includes Libya, to end co-operation with Turkey in protest against its military offensive against Kurdish forces in Syria.
Libya has been mired in chaos since a Nato-backed uprising that toppled and killed dictator Muammar Qaddafi in 2011.
Field Marshal Khalifa Haftar, whose Libyan National Army backs a rival administration, launched an offensive in April in a bid to seize Tripoli from militants allied to the GNA.
The November military deal was introduced in the Turkish Parliament on Saturday.
The maritime part of the deal expands Turkey's continental shelf in the Eastern Mediterranean.
A recent discovery of vast gas reserves has triggered an exploration scramble between adjacent states and international oil companies.
The Turkey-Libya agreement was strongly condemned by several countries, including Greece and Cyprus.
Mr Erdogan declared on Tuesday that Turkey was prepared to send troops into Libya if requested.
In another sign of the Turkey-Libya rapprochement, Ankara announced on Saturday that Libyans younger than 16 or older than 55 would be allowed to enter Turkey without visas.
Field Marshal Haftar on Thursday announced a "decisive battle" to wrest Tripoli from the GNA government.