Israel's vice-prime minister Silvan Shalom on Sunday said that the formation of a Lebanese government led by Hezbollah would be a "very, very dangerous development."
Lebanon is struggling to resolve a political crisis which erupted when 11 ministers affiliated with the Shia Hezbollah group resigned earlier this month, bringing down Prime Minister Saad Hariri's government.
The resignations came amid a dispute over a UN probe into the 2005 assassination of Hariri's father, former premier Rafiq Hariri, with reports suggesting the final conclusions will implicate Hezbollah members.
Lebanon's political parties are now jostling to try to form a new government, with Iranian-backed Hezbollah potentially leading any new coalition.
In an interview with public radio, Shalom said such a formulation "would be a very, very dangerous development, because we would in fact have an Iranian government on Israel's northern border."
Israel accuses Hezbollah of being financed and armed by Tehran.
Shalom said Hezbollah would be taking control of "a sovereign state, its army, its police and its security forces."
Israeli radio reported on Sunday that Prime Minister Benjamin Netanyahu was planning to hold talks with his government on the situation in Lebanon. The radio gave no further details.
A spokesman for Netanyahu, questioned by AFP, would not confirm or deny that the meeting would include discussions on Lebanon.
Shalom accused Iran of using Hezbollah in "a strategy that envisages the creation of a new Persian empire developing nuclear weapons and taking control of the Middle East and its oil resources while fomenting revolutions against the current regimes."
Iran denies having any ambition to develop nuclear weapons and says it is merely seeking nuclear power for peaceful purposes, despite accusations by Western powers and the Israeli state.
Beirut has been in political turmoil since the UN-backed Special Tribunal for Lebanon (STL) on Monday filed indictments for the 2005 murder of Rafiq Hariri.