Barak was speaking on Israel's Army Radio before a planned visit on Thursday by US armed forces chief General Martin Dempsey that has triggered speculation Washington will press Israel to delay any action against Tehran's nuclear program.
Barak's remarks suggest that Iran, which denies trying to make a nuclear bomb while defying international censure of its secretive uranium enrichment and missile projects, has not yet advanced past what Israel might deem a critical threshold.
Asked if the United States has asked Israel to tell them before any assault against Iran, Barak said, "We haven't made any decision to do this. This entire thing is very far off."
Barak also hinted that Israel -- presumed to have the only nuclear warheads in the region -- was coordinating with Washington its plans to deal with Tehran's nuclear project.
"I don't think our ties with the United States are such that they have no idea what we are talking about," he said.
When asked whether "very far off" meant weeks or months, Barak said, "I wouldn't want to provide any estimates. It's certainly not urgent." The March leadership election in Israel's main opposition Kadima party "will happen sooner," he said.
Iran says its nuclear work is solely for peaceful purposes. Barak said that, were the Islamic Republic to decide to enrich uranium to weapons-grade purity, it would first have to call off cooperation with the UN nuclear watchdog agency.
"Such an action would provide solid proof that indeed time has run out and this would be liable to either worsen the sanctions or other action against them," Barak said.
"They don't want this (more sanctions or other action). That's why they don't do it, not because they have given up their plan or because they have ceased advancing to achieve immunity for their operations," he said, the latter referring to Iran's activating an enrichment plant in a fortified mountain.
Asked for an assessment on how long it would take Iran to build a nuclear warhead, were it to make that decision, Barak said, "It's not a matter of years. There are those who say a year, or a year and half, it does not make much of difference."
"I don't want to relate to it as though tomorrow it will happen," he said.
International Atomic Energy Agency inspectors are monitoring all nuclear sites that Iran has declared but the West fears that Iran may build other sites in secret.
Western powers also worry that Iran will gradually enrich uranium to higher levels under IAEA inspection to reduce the time needed to process further to weapons grade, so that when and if it decides to, it can quickly take that stockpile and turn it into weapons grade material.
Dempsey, the top US military officer, is due to travel to Tel Aviv for talks in which Iran is certain to be one of the main topics. It will be Dempsey's first visit since becoming chairman of the Joint Chiefs of Staff in September.
In a Nov. 30 interview with Reuters, Dempsey said he did not know whether Israel would alert the United States ahead of any unilateral military action against Iran. He also acknowledged differences in perspective between the United States and Israel over the best way to handle Iran and its nuclear program.
JERUSALEM (Reuters) -- Israeli Defense Minister Ehud Barak said on Wednesday any decision about an attack on Iran was "very far off".