Two former Iranian parliamentarians known as vocal critics of the authorities on Thursday submitted their candidacy for next month's presidential election, AFP correspondents said.

Both Ali Motahari and Mahmoud Sadeghi had their candidacy for the 2020 parliamentary election rejected by the Guardian Council, an unelected body that also decides who is eligible to run for president.

The better known of the two, 63-year-old Motahari, served three consecutive terms as a member of parliament from 2008 to 2020.

Motahari gained notoriety for his diatribes against the ultraconservative and populist former president Mahmoud Ahmadinejad.

During his last term in parliament, he often criticised the way power is exercised and the repression of opponents.

He has repeatedly called for the lifting of the house arrest of Mir Hossein Mousavi and Mehdi Karroubi, the leaders of the "Green Movement" that contested Ahmadinejad's re-election in 2009.

Motahari, who has conservative views on some social issues, such as the compulsory veiling of women, has indicated that he intends to stand as an independent candidate.

Sadeghi, 59, is a lawyer who served one term in parliament until 2020, during which he was a voice for reforms.

Iranians are due to elect a successor to President Hassan Rouhani, who is constitutionally barred from running for a third consecutive term, on June 18.

Since registrations opened on Tuesday, more than 100 mostly unknown hopefuls have submitted bids to stand in the election with the interior ministry.

They have until Saturday to register, and the conservative-dominated Guardian Council is expected to announce its approved list of candidates on May 26 or 27.