The bill defines an array of punishments for violators of a mandatory dress code, including fines and prison terms.

On Wednesday, lawmakers approved the three-year duration of the legislation on a trial basis, with 152 voting in favour, 34 against, and seven abstaining.

The Guardian Council, a powerful oversight body consisting of clerics and legal experts, would need to approve the bill before it can be implemented.

The implementation of the legislation, which had been in the works for months, was not put to a parliament vote. It was approved last month by a special committee consisting of 10 lawmakers.

At the time, lawmakers invoked an article of the constitution that permits the formation of a committee to approve legislation for “experimental” implementation. Wednesday’s vote in parliament only decided the duration.

The legislation defines new frameworks for how Iranians, especially women, need to conform to the country’s mandatory dress code that has been in place since shortly after the 1979 revolution.

For women, unacceptable covering has been defined as “revealing or tight clothing, or clothing that shows parts of the body lower than the neck or above the ankles or above the forearms”, according to the latest version of the legislation released in local media.

For men, it has been defined as “revealing clothing that shows parts of the body lower than the chest or above the ankles, or shoulders”.

It also sets new punishments for people who are found to be in violation of the rules.

Totalling more than 70 articles, the bill defines an array of financial penalties for hijab violations, which could be ramped up to prison terms if found to be done in an organised manner and in contact with “foreign governments, networks, media, groups or organisations” or people affiliated with them.

Businesses and business owners will also be exposed to punishments, including hefty fines, bans on leaving the country, or prison terms if they are found to be propagating “nudity, lack of chastity or bad covering” in any way.

The bill also details new duties for a host of government, law enforcement and military organisations to make sure they and their staff fully comply with the mandatory hijab rules and do their utmost to prevent instances of violation or identify them.

Last month, a group of United Nations experts said the hijab bill “could be described as a form of gender apartheid”.

“The draft law imposes severe punishments on women and girls for noncompliance which may lead to its violent enforcement,” the experts said.

“The bill also violates fundamental rights, including the right to take part in cultural life, the prohibition of gender discrimination, freedom of opinion and expression, the right to peaceful protest, and the right to access social, educational, and health services, and freedom of movement.”

The bill was passed just days after the first anniversary of the death of Mahsa Amini, a 22-year-old woman from the northwestern province of Kurdistan who died in police custody in the capital Tehran.

Her death, after her arrest by morality police for alleged noncompliance with the mandatory dress code, sparked nationwide protests that lasted for months and left hundreds killed.

After largely vanishing from the streets of Tehran and other cities during the protests, morality police vans officially returned last month.

In recent months, authorities have taken a series of steps to counter increased instances of women ditching their hijabs online and in public.

These have included using smart cameras, fining owners of vehicles and then impounding the cars for repeated offences, forming court cases against celebrities, and shutting down businesses for offering services to women who are deemed to be violating mandatory dress codes.