The Iranian currency jumped about 9 per cent against the US dollar because of apparent government intervention and a positive tone at nuclear talks between Iran and world powers, currency websites and Iranian media reported on Monday.

The rial traded around 32,500-33,500 to the US dollar in the free market on Monday, compared to about 36,300 on Sunday, the reports said.

The currency lost more than half its value and hit record lows in 2012, battered by US and European economic sanctions which slashed Iran's oil earnings.

But the rial has regained some strength in the past week, rising about 2 per cent last Wednesday after talks on Iran's disputed nuclear programme with a group of world powers, known as the P5+1, in Kazakhstan. Although no breakthrough was reported in the talks, Iranian officials portrayed them as a positive step.

Since Sunday, the Iranian government appears to have provided larger supplies of dollars to the currency market, boosting the rial, Mehr news agency reported without giving details.

"Those active in the currency and coin markets see the widespread provision of hard currency to the market and the positive environment of negotiations between Iran and the P5+1 group in Almaty as the main factors in the drop in the price of coins and currency," the agency said.

Iranians can exchange their rials for hard currencies through loosely regulated money changers, though the government cracked down on the traders and arrested dozens after the rial's plunge last year.

The Fars news agency quoted an unnamed money changer on Monday as saying the rial's rebound this week had been so strong that many traders had stopped buying and selling currency until prices stabilised. – Reuters