File photo: Hezbollah MP Mohammed Raad
"We accept you as opponents in parliament, but we will not accept you as shields for the Israelis," said Mohammed Raad, according to Hezbollah's Al Manar TV channel.
In mid-2006, a 34-day war pitted Israel, whose troops had withdrawn from southern Lebanon in 2000, against Hezbollah.
Raad headed the outgoing parliamentary bloc led by Hezbollah and was re-elected Sunday in the first polls since the country's economy was dragged to the brink of collapse and a mass anti-government protest movement sparked hope for change in 2019.
His comment raised fears of unrest as the country awaits results Tuesday, which will show whether Hezbollah and its allies can keep an actionable majority in parliament.
"Don't become the fuel for civil war," Raad told opponents.
Lebanon suffered a 15-year-old civil war that ended in 1990 with most belligerents turning into political parties that have ruled the country for the past 30 years.
Independents from the country's nascent protest movement and members of Hezbollah's arch-rival, the Lebanese Forces (LF), are expected to make major gains in Sunday's polls.
Samir Geagea's LF, which has strong ties with Saudi Arabia, should emerge as the largest Christian party, at the expense of President Michel Aoun's Free Patriotic Movement (FPM), which is allied with Hezbollah.
Hezbollah, considered a "terrorist" organisation by many Western countries, has so far retained all its seats.
Hezbollah supporters last year accused LF gunmen of killing seven of their supporters during a protest in Beirut. The Christian group denied the charges.
Hezbollah is the only group that has kept its weapons arsenal after the country's civil war ended.