One of the sources said it was the first time such a seizure had been made. There was no immediate comment from Hezbollah, News.Az reports citing France24.
"The detainee and the seized funds will be handed over to the investigation division at the General Directorate of General Security," Lebanon's finance ministry said in a statement, without making a reference to Hezbollah.
Israel's military said earlier on Friday it had killed a Hezbollah weapons smuggler in a strike on eastern Lebanon a day earlier.
In a statement, the military accused the slain militant of having "recently been involved in transporting weapons from Syria to Lebanon".
The terms of a ceasefire agreed by Israel and Hezbollah in November require the Lebanese army to deploy into south Lebanon as Israeli troops and Hezbollah withdraw forces. Israel's Defence Minister Israel Katz said Thursday that Israel troops would remain in southern Lebanon "indefinitely".
Last month, Israel's UN ambassador accused Hezbollah of trying "to regain strength and rearm with the assistance of Iran". A senior Lebanese source close to Hezbollah denied the allegations.
Lebanon halted an Iranian flight to Beirut earlier this month after the Israeli military accused Tehran of using civilian aircraft to smuggle cash to Beirut to arm Hezbollah.
