Iranian women walk in a street in Tehran on Sunday. AFP

After they have been identified, violators will receive "warning text messages as to the consequences,” police said in a statement.

The move is aimed at "preventing resistance against the hijab law,” said the statement, carried by the judiciary’s Mizan news agency and other state media, adding that such resistance tarnishes Iran's spiritual image and spreads insecurity.

CCTV cameras ares seen in streets in Tehran. Reuters

A growing number of Iranian women have been ditching their veils since the death of a 22-year-old Kurdish woman while in custody of the morality police last September. Mahsa Amini had been detained for allegedly violating the hijab rule. Security forces violently put down the protests following her death.

But although risking arrest for defying the obligatory dress code, women are still widely seen unveiled in malls, restaurants, shops and streets around the country. Videos of unveiled women resisting the morality police have flooded social media.

An Iranian woman walks in a street in Tehran. AFP

Saturday's police statement on the hijab law called on owners of businesses to "seriously monitor the observance of societal norms with their diligent inspections”.

Under Iran's Islamic sharia law, imposed after the 1979 revolution, women are obliged to cover their hair and wear long, loose-fitting clothes to disguise their figures. Violators have faced public rebuke, fines or arrest.

CCTV cameras are seen in a street in Tehran. Reuters

Describing the veil as "one of the civilisational foundations of the Iranian nation" and "one of the practical principles of the Islamic Republic,” an Interior Ministry statement on March 30 said there would be no retreat on the issue.

It urged citizens to confront unveiled women. Such directives in past decades have emboldened hardliners to attack women. Last week a viral video showed a man throwing yoghurt at two unveiled women in a shop.

Reuters