The group, which opposes the Syrian presence in the country, was on the way to the mountain village of Bteghrine to meet with Gabriel Murr, the uncle of Interior Minister Elias Murr.
Around 12 armed men blocked the group's passage in the village, and ordered MP Nassib Lahoud not to continue his journey.
They threatened him saying he would be "a dead man" if he tried to go to the lunch, according to Gabriel Murr, a campaigner against Syria's dominant role in Lebanese politics.
The men fired several shots in the air, he said.
Individuals accompanying Lahoud confirmed the incident, saying
it took place in view of police officers who did not intervene.
Gabriel Murr's television station MTV and its sister radio RML
were shut down in September, causing an uproar among Christian opposition groups.
The Lebanese court which ordered their closure said the media institutions had harmed relations with Syria and criticised President Emile Lahoud.
The stations were seen as the main media voice for the Christian
Syria dominates Lebanon politically and maintains about 20,000
troops in the country.
It first intervened in the country during the Lebanese civil war in 1976.
According to the Taif agreement reached in 1989 Damascus should have completed its troop withdrawal in 1992.