IRAN is much more vulnerable to pressure than the West realises, and ratcheting up the pressure with sanctions may halt its nuclear weapons program, according to an Israeli specialist on Iran.

The European Union's history with Iran taught it that it could mock the West, but sanctions passed on Monday had real teeth, Emanuele Ottolenghi of the Brussels-based Foundation for the Defence of Democracies said in Melbourne yesterday.

But he and David Menashri, director of the Centre of Iranian Studies at Tel Aviv University, said that pressure would work if resolutely applied, including sanctions, downgrading diplomatic relations, stopping the leaders' families studying and shopping abroad, and broadcasting into Iran.

''If they get the bomb they won't use it immediately. They will use it to project their power and create mischief,'' Dr Ottolenghi said.

He said the Russians, ostensibly helping Iran with a nuclear reactor and modern missile defence system, were delaying their aid. They did not want a nuclear-armed Iran, but liked to see the Americans sweat.

Dr Menashri said ordinary Iranians were disenchanted at the lack of progress since the revolution toppled the Shah 31 years ago, and change would come from within.

''Frustration is higher now than at any time since the revolution,'' Dr Menashri said.

''[Last year's] election showed the nature of the regime and the level of disillusionment.''

But Iranians were not happy with the world's reaction.

US President Barack Obama promised support for freedoms, but when the people took to the streets he disappeared for 10 days, Dr Menashri said.

''Now the world, including Australia, is looking at Iran. Such a radical ideology as that espoused by President Ahmadinejad, when it goes with nuclear capability, is something the world cannot tolerate,'' he said.

He said that if Iran got the bomb the world would pay a huge political price, including a Middle Eastern arms race.