Israeli Foreign Minister Avigdor Lieberman said Thursday he believes "the Arab Spring will be followed by a Persian Spring," with international sanctions against Iran leading to renewed domestic unrest.

His remarks came a day after scuffles broke out in central Tehran in the first sign of unrest over Iran's plunging currency, which has lost more than half its value since last week as European and US sanctions have bitten.

"The Arab Spring will be followed by a Persian Spring, instability is spreading in Iran, and not just in Tehran," Lieberman told Israeli military radio.

"There is no doubt that the protest movement will be strengthened by the approach of the Iranian presidential elections next summer," he added.

"The Iranian regime is reaching a critical point. International sanctions will not convince the leaders of the country to renounce their nuclear programme, but what is important is that the Iranian people have begun to realise that they are not ready to be sacrificed to satisfy the revolutionary and fanatic ambitions of their leaders," he said.

Iranian President Mahmoud Ahmadinejad's rivals claim that economic mismanagement is the main cause of the currency crisis. He blames Western sanctions but insists Iran will make no concessions on its nuclear programme.

Lieberman called on Western governments to act to help opposition activists who rose up against the regime when Ahmadinejad was re-elected in 2009 and the most prominent of whom remain under house arrest.

"This time, the West must help the movement, facilitating its communications, giving money and mobilising international organisations like the UN Security Council, the European Union and other bodies," he said.

Iran has faced increasingly tough sanctions, championed by Washington, over its nuclear programme, which Israel and much of the international community believe masks a weapons drive.

Israel, the sole if undeclared nuclear power in the Middle East, says a nuclear-armed Iran would pose an existential threat to the Jewish state and that it reserves the right to take military action to prevent Tehran obtaining a weapons capability.