The parliamentary majority bloc wants Hezbollah to give up its arsenal. Hezbollah says its weapons are necessary to protect against Israeli attacks. Participants said various proposals would be studied.
Three of the participants - Amin Gemeyel, a former president, Samir Geagea, leader of the right wing Lebanese Forces (LF) political party, and Michel Aoun, the Syrian-backed Christian opposition leader - submitted defence proposals.
"Mohamed Raad [Hezbollah MP] said during the meeting that Hezbollah also has a defence strategy it will submit on paper," one participant said.
Hezbollah has faced sustained allegations of rearming illegally from Syria in breach of a 2006 UN Security Council resolution that brought the conflict to a close.
Monday's session follows two rounds of talks in September and November and was attended by 14 leaders representing each of the main parliamentary blocs.
Lebanon endured a damaging 18-month political crisis that brought the country close to civil war earlier this year before a Qatari-brokered deal between the rival groups.
Talks have been adjourned until January 22.