TEHRAN (Reuters) - Iran's parliament approved on Sunday the last three ministers in President Mahmoud Ahmadinejad's 21-member cabinet after rejecting his original choices in September, the semi-official ILNA news agency said.

Parliament voted to support Ahmadinejad's new candidates for the energy, welfare and education portfolios, although deputies criticized the nominee for the welfare job for mismanaging a disputed June 12 presidential election.

Eighteen of Ahmadinejad's proposed ministers had won parliamentary approval in September after Supreme leader Ayatollah Ali Khamenei called on the assembly to cooperate with the president.

The June election sparked huge protests by the opposition which said it was rigged -- an accusation rejected by authorities, including Khamenei. The protests plunged Iran into its deepest internal crisis since the 1979 Islamic Revolution.

Of the three nominees in parliament on Sunday, lawmakers criticized proposed welfare minister Sadeq Mahsouli over the June poll.

Seven months before the disputed vote, Mahsouli took charge of the interior ministry responsible for overseeing elections after the previous minister was sacked by lawmakers over a fake university degree.

"The interior minister is in charge of domestic security ... Mahsouli was in charge when bitter events happened at the Kahrizak detention center and ... Tehran University dormitory," said conservative MP Ali Motahari, ILNA reported.

Khamenei in July ordered the closure of Kahrizak detention center south of Tehran, after at least three people died in custody there and widespread anger erupted as news spread of conditions in the jail.

Thousands of people were arrested in protests after the June vote. More than 100 people, including moderate senior officials, lawyers, activists and students still remain in jail.

The opposition says more than 70 people were killed in the post-election unrest. Officials say the toll was half that.

Mahsouli, a former Revolutionary Guards comrade of the president, had been a nominee for oil minister in Ahmadinejad's first term but withdrew after lawmakers criticized his lack of related experience and his wealth.

Lawmaker Motahari repeated the criticism over the source of Mahsouli's wealth, accusing him of using his previous positions to acquire it.

"Such an enormous wealth would not accumulate naturally," Motahari said, ILNA reported. (Additional reporting by Ramin Mostafavi, Writing by Parisa Hafezi; Editing by Charles Dick)