Iran has sentenced a popular rapper to six years and three months in prison over his participation in protests that rocked the country last year, his supporters say.

A social media account run by supporters of Toomaj Salehi announced the sentence, as did Ye-One Rhie, a member of the German Parliament who has campaigned on his behalf. There was no immediate word from Iranian authorities.

Salehi was among thousands of mostly young Iranians who took to the streets last year after the death of Mahsa Amini.

Ms Amini, a 22-year-old woman, died after she was arrested by Iran’s morality police for allegedly violating the country’s strict Islamic dress code. 

The protests spread across the country and quickly escalated into calls for the overthrow of Iran’s clerical rulers.

The Iranian rapper, aged 33, was arrested last October, after criticising his government in songs and music videos that were widely circulated online.

“Someone’s crime was dancing with her hair in the wind,” he raps in a video with over 450,000 views on YouTube — an apparent reference to Ms Amini.

In another verse, he predicts the downfall of Iran’s theocracy. “Your whole past is dark, the government that took the light out of the eyes … We go from the bottom of the pyramid and knock to the top … Forty-four years of your government, this is the year of failure”.

After Salehi’s arrest, state media released a video showing him blindfolded and apologising for his words, a statement likely made under duress. Rights groups say Iran routinely tortures prisoners into making false confessions.

Following the protests, authorities launched a heavy crackdown in which more than 500 people were killed and nearly 20,000 arrested, according to Human Rights Activists in Iran. Authorities have said many of those detained were released or given reduced sentences.

The protests largely died down earlier this year, but there are still widespread signs of discontent.

Iran has executed a total of seven people in connection with the protests, accusing them of attacking security forces. 

They were convicted in secretive courts where rights groups say they were denied the right to defend themselves. Salehi’s supporters had feared that he too could face the death penalty.

-AAP