Speaking on a visit to Moscow, he said it was not Israel's job to deal with Iran alone, which he described as "a threat to the entire world order".
Israeli PM Benjamin Netanyahu says Iran cannot be allowed to have nuclear arms and refuses to rule out use of force.
Iran denies it seeks nuclear arms and says its programme is totally peaceful.
Israel, which is widely believed to be the Middle East's only nuclear-armed state, has repeatedly described Iran's uranium enrichment programme as a threat to its existence.
Speaking in Russian, Mr Lieberman said: "I have been asked by Saudi journalists about when Israel plans to bomb Iran. We are not planning to bomb Iran."