Protesters have shut down major cities in Iran for most of this week, angry about the country's economy and alleged corruption and mismanagement from its theocratic government.

The protests began when merchants in the capital, Tehran, shut their shops in response to a currency crash, with the Iranian rial sinking to a record low against the US dollar on December 29.

They have since spread across other demographics and cities, with people demanding Iran's leaders end the country's clerical rule and hold free elections.

Several people have been killed in the unrest, including three protesters in an attack on a police station in the province of Lorestan, according to the semi-official Fars news agency.

Authorities have also confirmed one death in the western city of Kuhdasht, and rights group Hengaw reported another death in the central province of Isfahan.

"These protests are a hunger revolution, this is truly a bread revolution," Farideh*, told the ABC from Tehran.

"People have been pushed to desperation. When you look into young people's faces, you see sadness and exhaustion. Even though they work and are educated, they can't afford a pair of trainers or to replace a mobile phone. They're hungry. Everyone is hungry."

Merchants from Iran's bazaars played a key role in the 1979 Islamic Revolution, which brought Iran's clerics to power.

Now they may have started a movement to depose those rulers because many of the protesters want more than economic relief.

Shuttered shops in the Tehran Grand Bazaar in Iran. (Majid Asgaripour/WANA via Reuters)

Some told the ABC they were angry about extensive corruption and decades of mismanagement and wanted an entirely new system of government.

"This anger comes from the sense that the country has been abandoned, as if no-one intends to stop the collapse, the instability, or the soaring prices," Babak* told the ABC.

"It feels like none of this matters to the ruling power, and no-one is making an effort to even acknowledge the lower-income groups who make up the majority of society.

"I hope this pressure continues until we reach an outcome because the bazaar has the power to break the back of this government and take it down. I hope the protests continue."

The currency crash came after other crises weakened Iran's clerical regime — a massive water shortage in Tehran and the 12-day war with Israel in June, in which the Iranian military was unable to defend Tehran and other cities against daily strikes.