Tehran (AFP) - Iran has excluded Hassan Khomeini, grandson of the founder of the Islamic republic and a cleric with ties to reformist politicians, from contesting elections to the country's powerful Assembly of Experts.

The decision, revealed by Khomeini's son on Tuesday, was taken by the Guardian Council, a conservative-dominated committee that decides who can run for public office.

Khomeini was among hundreds of candidates ruled out of standing for the assembly, which monitors the work of Iran's supreme leader, Ayatollah Ali Khamenei.

With an eight-year term of office, its 88 members may also be responsible for picking the 76-year-old's eventual successor.

The rejected candidates have until Saturday to appeal.

Voting for the assembly will take place on February 26, the same day as parliamentary polls.

Following Iran's recent nuclear deal with world powers led by the United States, both elections are seen as crucial to shaping the country's future direction.

Khomeini is the grandson of Ayatollah Ruhollah Khomeini, the leader of the 1979 Islamic revolution that ended the reign of US-backed Shah Mohammad Reza Pahlavi.

The elder Khomeini, a firebrand conservative who railed against pervasive Western influence, died in 1989.

He remains revered -- his image present in every public office, on Iranian banknotes and on countless murals in Tehran and other cities.

His grandson's candidacy for the assembly would have been the first time since the late leader's death that the famous family name would have been returned to politics.

At 43, Khomeini is significantly younger than most of the current members of Assembly.

- Not religiously competent -

But he was not verified as having sufficient religious competence to contest the ballot, his son said on his Instagram account, which has 199,000 followers.

In a post including a picture of his father studying religious texts, Ahmad Khomeini said the Guardian Council verdict came despite "testimony from dozens of religious authorities".

Story continues

"It became definite last night (Monday)" that his father had not been classed as "mojtahed", or sufficiently learned in Islam, to take a place on the assembly, he wrote.

A member of the Guardian Council said on January 5 that Khomeini had failed to attend a qualifying exam.

But in his post Khomeini's 18-year-old son cast doubt on that being the grounds for his father's exclusion.

"In my opinion the reason for non-verification is clear to everyone, especially given that some others' ijtehad ("knowledge" in Farsi) has been verified without them sitting for the exam," he wrote.

The Assembly of Experts is comprised solely of clerics. A final list of candidates is expected on February 9.

- Hundreds of candidates rejected -

Around 800 candidates announced bids in December to join the assembly, opening the door to the verification process.

A spokesman for the Central Elections Supervising Committee, the vetting arm of the Guardian Council, said 166 candidates had been approved for the Assembly election, 111 were not authorised, 207 were disqualified and 158 had withdrawn.

A further 152 candidates did not attend the qualification exam, Siamak Rah-Peyk said on state television.

The younger Khomeini has not previously been a prominent public figure but his candidacy was contentious because of his ties to reformists, including Mohammad Khatami, Iran's president between 1997 and 2005.

Khatami is no longer publicly active, at least partly because a court order bars his image or comments being used in domestic media.

Tension between reformists and conservatives has been high since a presidential election in 2009 saw Mahmoud Ahmadinejad, a hardline critic of the West, returned to office.

That election's two reformist hopefuls, Mir Hossein Mousavi, a former prime minister, and Mehdi Karroubi, a two-time parliament speaker, alleged widespread ballot fraud cost them victory.

The two men, and Mousavi's wife, have been held under house arrest since 2011.

Long sidelined, reformists have regrouped since the election in 2013 of President Hassan Rouhani -- a moderate who pledged to end the nuclear crisis -- and they have been hoping for a comeback in next month's elections.

Despite backing the nuclear deal, Khamenei has warned that it could lead to "infiltration" in Iran from US economic interests and cultural influence.