Army chief of staff General Moshe Yaalon said Israel was concerned about intelligence assessments that Tehran could build an atomic bomb by 2007.
"Political pressure certainly has potential, just as it worked on Libya. And this must be exhausted first of all, in my view," he said.
Although Tel Aviv ordered the bombing of Iraq's Osiraq reactor in 1981, Yaalon said Israel does "not necessarily" have to resort to military action to counter the alleged threat.
But Iran has denied accusations that it is using a civilian atomic programme to hide efforts to develop nuclear arms.
It argues that its atomic ambitions are limited to generating electricity and that it has signed the Nuclear Non-Proliferation Treaty (NPT) and the Additional Protocol that allows for unannounced inspections by UN officials.
Israel has not signed the NPT and refuses to confirm if it possesses about 200 nuclear warheads, as international organisations estimate.
On Monday, Iran vowed harsh retaliation if its nuclear facilities were attacked by Israeli forces.