Another man wanted by authorities for suspected espionage escaped to Israel on May 5, according to a senior security official.
Lebanese citizens who try to sneak into Israel are normally detained, questioned and sent back to Lebanon.
No Israeli response
There was no immediate word from Israel, which has declined to comment on the recent espionage allegations.
Nine of the 15 people arrested on suspicion of espionage in recent weeks have been charged with collaborating with Israel.
They include a retired general, his wife and his nephew, a government security agent.
Lebanon considers itself at war with Israel and spying for or collaborating with the neighboring country can be punishable by death.
The arrests, mainly in southern Lebanon, appear to have targeted those suspected of gathering information about Hezbollah fighters for Israel's Mossad intelligence agency.
Hezbollah fought a 34-day war with Israel in 2006, which killed 1,200 people in Lebanon and 159 in Israel.
In a related development, Hassan Nasrallah, the Hezbollah chief, said in a televised speech on Monday that his fighters would be on high alert during possible Israeli military manoeuvres.
He said the five-day military exercise will begin on May 31, but Israeli defence officials said on Friday that no date had been set yet for the joint US-Israeli war games.
"We don't believe that the Zionist enemy will launch a war" against Lebanon, Nasrallah said.
"But we will be present, ready and awake."
"If Israel plans on pulling anything during the manoeuvres, we're sending it a message that we stand ready and they will fail.
"We will not bury our heads in the sand.
Nasrallah's speech comes in advance of the crucial June 7 legislative election in Lebanon, in which his alliance could wrest the parliamentary majority from a Western-backed Sunni-led coalition.