Tehran (AFP) - The son of Iran's former president Akbar Hashemi Rafsanjani has been sentenced to 15 years in jail after being convicted of security offences and financial crimes, state media said Sunday.

Mehdi Hashemi was accused of involvement in massive protests that followed Iran's disputed presidential election in 2009, and after being threatened with arrest he left for Britain.

The now 45-year-old was detained and questioned after returning to Tehran in September 2012, and although he was bailed after nearly three months in custody he was later rearrested.

His conviction relates to national security matters as well as fraud and embezzlement, judiciary spokesman Gholamhossein Mohseni-Ejeie was quoted as saying on its official website and in state media.

Hashemi has 20 days to appeal his punishment, additional terms of which include an undisclosed fine and ban from holding public office, the reports said. One of his lawyers told the ISNA news agency that an appeal would indeed be lodged.

The 15-year sentence, if confirmed by a secondary court, would be one of the heaviest ever handed down to a family member of such a high-ranking official.

Hashemi supported the so-called Green Movement led by the defeated reformist candidates Mir-Hossein Mousavi and Mehdi Karroubi after the presidential election which was officially won by Mahmoud Ahmadinejad.

Rafsanjani's son is not the first member of the family to be convicted in recent years.

In September 2012, the former president's daughter Faezeh Hashemi, who also supported the Green Movement, was convicted of spreading propaganda against the regime. She was sentenced to six months in jail.

- Former oil sector official -

The name of Mehdi Hashemi, most commonly described as a businessman in recent years, was quoted in cases around a decade ago involving Norway's Statoil and the French oil giant Total, which were alleged to have paid bribes to secure easier access to Iran's hydrocarbons market. Hashemi was a senior official in the oil sector at the time.

Story continues

In the 2009 election he actively supported Mousavi, dismissing Ahmadinejad's winning of a second term as fraudulent.

Mousavi, along with his wife Zahra Rahnavard, and Karroubi were placed under house arrest in 2011 after repeatedly challenging the official election results.

Mousavi, a former prime minister and Karroubi, parliament's former speaker, are accused of "sedition" against the regime, and their most hardline opponents have said the two men should face the death penalty.

Rafsanjani, who was president from 1989 to 1997 and is now considered a moderate, is close to the reformist camp in Iranian politics.

In 2009, he became the bane of conservatives who have publicly echoed the doubts of some Iranians on the fairness of the election and criticised the repression and deadly crackdown by the regime that followed.

The protests remain a touch paper issue in domestic politics, with critics of the indefinite house arrests saying Mousavi, his wife and Karroubi should face a trial where they can defend themselves.

Rafsanjani, 80, has steadily fallen out of favour at the very top level of Iranian political office in recent years.

Last week he was heavily defeated by a hardline opponent in a closed vote to head the Assembly of Experts, the Islamic republic's top clerical body, which is responsible for picking the supreme leader and monitoring his performance.

And although he still holds several official roles he was barred from standing in the 2013 presidential election, officially because of his age. He threw his support behind the eventual winner, Hassan Rouhani.