Government soldiers seized a truck near Beirut last week carrying weapons to the group. Elias Murr, the defence minister, said the army would keep the weapons to fight Israel if it attacked.
Nasrallah said: "We are ready to provide the army with all the weapons that it requires."
"We have plenty of weapons, of all kinds ... and we have the right to transport our arms to combat Israel, even if we transport them in secret to hide them from the Israeli enemy," he added.
"The resistance will always stand by the Lebanese army, with our weapons, men and blood ... to defend Lebanon."
Anti-government campaign
The secretary general of Hezbollah also vowed to that the opposition campaign demanding that Fuad Siniora, the prime minister, step down, would continue.
"No one should imagine that the opposition's coffers have emptied," he said. "If the [demands] are not met, the opposition will continue its actions by means which it finds appropriate."
Opposition supporters have been staging a sit-in outside the offices of Siniora in central Beirut since December 1.
However, Nasrallah insisted that Hezbollah would not incite a conflict that could degenerate into a civil war.
"Civil war is a red line," Nasrallah said, an expression he also used last month after clashes between pro- and anti-government supporters that killed eight people.
Nasrallah, whose group is joined in the opposition by Shia, Christian, Druze and Sunni factions, has urged bilateral meetings with the government to end the crisis.
They want a unity government which would give them greater representation and an effective veto.