Iranian police arrested pop singer Mehdi Yarrahi on Monday for releasing a song against women's compulsory wearing of the veil, the judiciary said.

A day earlier, the judiciary's Mizan Online website announced that a "legal case" had been filed against Yarrahi "following the release of an illegal song which defies the morals and customs of the Islamic society."

The singer has now been "arrested by order of the Tehran prosecutor," Mizan Online said on Monday.

The action comes almost a year after the September 16 death in custody of Iranian Kurd Mahsa Amini, 22, triggered months of protests around the country.

Amini had been detained for alleged breach of the Islamic republic's strict dress code requiring that a woman's head and neck be covered.

Yarrahi was defiant after announcement of the "legal case".

"Don't cry, I am the nightmare of this judge", he said in a message posted on X, formerly Twitter, adding that "let's continuously talk about the anniversary of Mahsa Amini's murder."

Authorities have contested accusations by Amini's family that she died from beating.

Yarrahi, 41, on Friday released the song called "Roosarito", which means "Your Headscarf" in Farsi, expressing support for last year's protest movement.

Yarrahi's three-minute video clip incorporated the protest movement's slogan, "Woman, life, freedom."

He called on women to "take off their (head)scarves", and the video included short clips of several women dancing with their hair uncovered.

Mizan had said the legal measures against Yarrahi will also cover another "controversial song" he released in October. Titled "Soroode Zan" or "Woman's Anthem", it became a feature of the protest movement, particularly in universities.

During the months of protest, which Tehran generally labelled as foreign-instigated "riots", thousands of Iranians were arrested and hundreds killed including dozens of security personnel.

In July an Iranian court sentenced prominent rapper Toomaj Salehi, 32, who had backed the protests, to six years and three months in prison for "corruption on earth", one of the Islamic republic's most serious offences.

Iranian women have increasingly flouted the strict dress code since the mass protests began calling for an end to compulsory headscarves.

Last month, state media said police had relaunched patrols to catch those who leave their hair uncovered in public.