Iran's currency has slid 20 percent against the dollar in the last week despite central bank intervention, and Iranians concerned about the economy said on Tuesday, Jan 10, attempts to send text messages using the word "dollar" appeared to be blocked.

The central bank reportedly pumped $200 million into the market last week after new and much tougher U.S. sanctions prompted nervous Iranians to change rials into hard currency, accelerating a rise in the price of dollars on the open market.

Saying it would act to stabilize the currency, the Central Bank of Iran (CBI) imposed a rate of 14,000 rials to the dollar - up from record lows of around 18,000 rials - but many exchange offices would not sell at that price.

By Tuesday, the dollar price had risen again to around 17,000 rials, according to exchange bureaus, 50 percent more than the CBI's "reference rate" of 11,240 rials. The currency slide is a huge risk for consumer prices in a country where inflation is already around 20 percent and rising.

In a hint of political sensitivity over the issue, Iranians, long used to controls over Internet and mobile communications, said they were unable to send text messages contain the word "dollar".

The inflationary pressure comes a year after President Mahmoud Ahmadinejad's government slashed subsidies on food and fuel, sending historically cheap gasoline and utility prices soaring. Items like food, clothes and electronics have also become much more expensive to buy from abroad, and domestic manufacturers will have to pay more for imported intermediate goods.

The currency problem is a major political headache for Ahmadinejad ahead of March 2 parliamentary elections, not least because it could be seen as a consequence of the sanctions he has long said would not hurt the economy, Reuters reported.