Kol Israel radio made the claims citing Israel intelligence sources and said that Hezbollah now has 40,000 rockets capable of reaching Israel.
Prime Minister Ehud Olmert told a cabinet meeting Wednesday that the increase in weapons by Shiite Hezbollah was in violation of UN Resolution 1701, which ended the 34-day war in 2006.
The UN resolution called for the disarming of all militias and the prevention of gun-running and smuggling operations in Lebanon.
Over the past few days, Israeli Defense Minister Ehud Barak has raised the issue with foreign ministers from France, Germany and Italy.
According to Kol Israel, he indicated that Israel would not tolerate violations of peace agreements, which could damage "the fragile balance on the Israeli border."