Israeli Defence Minister Ehud Barak on Thursday ruled out a strike against Iran's nuclear facilities "for the moment," in remarks to public radio, but said that the Jewish state would keep all options open.

"We have no intention of acting for the moment... We should not engage in war when it is not necessary, but there may come a time or another when we are forced to face tests," Barak said.

"Our position has not changed on three points: a nuclear Iran is unacceptable, we are determined to stop that, and all options are on the table," he added.

Israel and much of the international community fear that Iran's nuclear programme masks a drive for a weapons capability. Tehran denies any such ambition and says the programme is for peaceful civilian energy and medical purposes only.

Israel has pushed Washington and the EU for tough sanctions against Tehran, but warned that it would not allow Iran to obtain nuclear weapons, and that military action to stop the programme remained an option.

Barak said he was confident that military action against Iran would not be devastating for Israel.

"War is not a picnic, but if Israel is forced to act, we won't have 50,000, 5,000 or even 500 dead, so long as people stay in their homes," he said, noting that rockets fired at Israel by Iraq during the 1991 Gulf War had not killed a single Israeli.

Asked about potential differences between the United States and Israel on tactics to stop Iranian nuclear development, Barak stressed that the Jewish state would ultimately take the decisions it thought best.

"It must be understood that Israel is sovereign. The government, the army and the security services are the only ones responsible for the security and the existence of Israel," he said.

Barak declined to comment on what was behind at least two explosions in Iranian cities in recent weeks, only one of which has been confirmed by Iranian authorities.

"Anything that sets back the Iranian nuclear programme, whether it is accidental or the product of other methods, is welcome," he said, refusing to say whether Israeli forces had any role in the incidents.

Former Mossad chief Meir Dagan reiterated his contention that Iran is sufficiently far from having nuclear weapons, and emphasised his objection to a military strike at this timepoint.

"The military option should be the last alternative," he said in an interview broadcast Thursday on Israel's private-run Channel 2. "All other alternatives should be realised before entering a conflict you know how will begin, but have no way of predicting all the aspects of its continuation."

In remarks made public immediately after stepping down as head of the Mossad in January, Dagan estimated Iran would not have a nuclear weapon before 2015.

On Thursday, he evaluated that the world would have sufficient time to respond, if and when Tehran hits the final plateau of achieving nuclear military capability.

"The Iranians, to this point, have walked this route very carefully," Dagan said. "When they (Iran) break into the final stage" of developing a nuclear weapons, "they will enter a deep dispute with the international community, and therefore I think we will have sufficient advance notice."

"In this timetable, we will have enough time to reach an extreme decision of employing military force."

The International Atomic Energy Agency, the UN nuclear watchdog, last month warned it had "credible" information that Iran was carrying out "activities relevant to the development of a nuclear explosive device."

According to the report, dated November 8, Iran has produced 4,922 kilograms, nearly five tonnes, of uranium enriched to 3.5 percent, as well as 73.7 kilograms of uranium enriched to around 20 percent.

On Monday, Brigadier General Itai Brun, head of research for Israeli military intelligence, told lawmakers he estimated that Iran was "using 6,000 centrifuges regularly, out of 8,000 installed."

"Until today, they have managed to accumulate approximately 50 tonnes of low enriched uranium, and a bit less than 100 kilos of 20 percent enriched uranium," he said.

Brun said Iran would need at least 220 kilos of 20 percent enriched uranium if it decided on a drive for the much higher levels of enrichment necessary to produce a nuclear weapon.

Israel is widely reported to have the Middle East's sole but undeclared nuclear arsenal.