Nasr Allah made the comments on Friday during a ceremony marking the 26th anniversary of the capture of Samir Kantar, Israel's longest-held Lebanese prisoner. Kantar, a Lebanese fighter, has been in an Israeli prison since 1979 for killing three Israelis.
Israel has said it will not release Kantar before getting information about Ron Arad, an Israeli navigator whose plane was shot down over Lebanon in 1986.
Israeli media has in the past speculated Arad had been taken to Iran, but Tehran denied the reports.
Hizb Allah has promised to find concrete information about Arad, but on Friday Nasr Allah said he strongly rejected linking the release of Lebanese prisoners to the Israeli pilot.
"If we are able to get something about Arad that opens the way for a solution, then this is good," he said. "We refuse to link the fate of brothers that exist with a human being whose fate is unknown."
The Hizb Allah leader also expressed hope for the release of Nasim Nisr, a Lebanese-born Israeli captured for having contacts with Hizb Allah, and Yahia Skaff, who was detained while taking part in a Palestinian attack that killed 35 Israelis.
Nasr Allah said German-led mediation for the exchange of prisoners between Lebanon and Israel might soon end in failure.
"When we fail in negotiations, and that should be determined soon, we will only have one choice left in front of it. It is what brought back some of the brothers who are among us now," he said referring to last year's exchange of an Israeli reserve colonel and the remains of three Israeli soldiers in return for hundreds of Arab prisoners.