"If I am elected president of the republic, I shall open up dialogue at the presidential palace and I will preside over it," he said.
Lebanon has faced a political crisis since November, when Hezbollah and its allies pulled their six ministers out of the cabinet of Fouad Siniora, prime minister and a key March 14 member.
|"We need to consecrate the principle of the state holding a monopoly on arms while not disavowing the sacrifices of the Resistance [Hezbollah]"|
Boutros Harb, MP and presidential candidate
The political opposition has called for the formation of a national unity government, which would grant them a veto over cabinet decisions.
Efforts by the Arab League and France to broker a compromise between the ruling bloc and the opposition have not produced any breakthrough.
Parliament is due to convene on September 25 to begin the task of electing a replacement for Emile Lahoud, who has close links to Damascus.
A successful vote requires the 128-seat house to gain a necessary quorum of 86 deputies.
Siniora's ruling coalition has just 69 MPs, meaning that it will have to reach a compromise with the political opposition for a president to be elected.
Lahoud said on Thursday that he would appoint an interim government headed by Lebanon’s army chief if no agreement is reached on a president by the time his term expires on November 23.
"The government which is still standing and which is unconstitutional... cannot assume power if the election of a president of the republic is not possible," said Lahoud in reference to Siniora's cabinet, which the Hezbollah-led opposition has boycotted.
If Lahoud were to set up an interim administration, Lebanon would effectively have two governments, assuming that Michel Suleiman, army commander, were to accept the job.
Lebanon's Christian community is divided between those who support the parliamentary majority and followers of Michel Aoun, a former acting president who is allied to Hezbollah.
If differences between the two political camps persist, Lebanon could end the year without a head of state.
Many fear such an outcome could destabilise the country even further.
Harb stressed the need to "find an honourable solution" to the disarmament of Hezbollah, which has been stipulated in UN Security Council resolutions.
"We need to consecrate the principle of the state holding a monopoly on arms while not disavowing the sacrifices of the Resistance [Hezbollah]," he said.
Harb also said an "historic reconciliation with Syria" should be sought.
Relations with Damascus deteriorated after the assassination of Rafiq al-Hariri, a former Lebanese prime minister, in 2005.
Widespread public demonstrations in Lebanon shortly after al-Hariri's death forced Syria to pull its troops and security officers from its neighbour after a 29-year stay.
Syria has been widely blamed for a string of political murders in Lebanon. Damscus denies the accusations.