Lebanese opponents of the Syrian-backed government have united under a joint banner for the first time since the civil war started in 1975.
Opposition unity brings old civil war foes under the same banner
Right- and left-wing groups from across Lebanon's divided Christian, Druze and Muslim communities were represented.
The action plan includes a new election law to "ensure representation for all Lebanese political sensibilities".
Politicians called for an end to what they see as interference by Syria which keeps 14,000 troops on Lebanese soil.
The opposition groups included former warlord and Druze leader Walid Jumblatt's leftist party, the Free Patriotic Movement (FPM) of exiled former Prime Minister and warlord General Michel Aoun, the Lebanese Forces and former Prime Minister Rafik Hariri's parliamentary bloc.
Habib Sadeq, head of the Democratic Forum, said: "The opposition is committed to working towards a sovereign and independent Lebanese state, free of all foreign interference, especially the Lebanese and Syrian intelligence services."
In remarks quoted by the AFP news agency, he accused the intelligence services of turning Lebanon into a "police state" and called for a restoration of democracy and the possibility of power transfer.
Former Lebanese president Amine Gemayel was quoted as saying that the political climate resembled 1943 "when all Lebanese fought side by side for independence from French rule".
Mr Jumblatt is currently embroiled in a controversy with the government over the removal of security barriers around his Beirut home at the weekend.
His right-hand man was the target of an assassination attempt in October and he said he had received death threats.
He said he did not know who had removed the barriers but "if anything were to happen to me, it would be very bad for all those in charge of security in Lebanon".
Most Lebanese politicians and former politicians' homes are surrounded by heavy security measures provided by the government - a legacy of sporadic violence since the civil war.
Newspapers reported on Monday that Syria's military intelligence chief in Lebanon, Rustom Ghazaleh, had phoned Mr Jumblatt to assure him that no harm would come to him because of his political stance.
A former ally of Syria, Mr Jumblatt became its most trenchant critic over its continued domination of Lebanon's politics and security.
He also spearheaded opposition to the extension to Syrian-backed President Emile Lahoud's term in office in September.