Two thirds of Iran's MPs have written to the president urging him to take measures to ensure women correctly observe Islamic dress, denouncing Western cultural influence against the veil.
The 195 members of the 290-strong parliament who signed the letter in part blamed satellite television for feeding the trend, ISNA news agency reported on Sunday.
A defining feature of Iran's interpretation of Islamic law since the 1979 revolution, hijab obliges women to cover their hair and much of their body in loose clothing when outside, regardless of their religion.
A dedicated "morality police" has long handed out fines, verbal notices or even arrested women it considers are not properly observing the rules, but lawmakers have in recent months criticised lax enforcement.
In the letter, the MPs wrote: "One of the main areas of cultural invasion is in trying to change the way of life of Iranians regarding the veil. We ask that you give the necessary orders to enforce the law."
Iran's parliament is dominated by conservative males.
Signup to our newsletter and follow us on Facebook and Twitter!
However, President Hassan Rouhani, a self-declared moderate who was surprisingly elected last June, has expressed a desire to expand social freedoms -- to the disapproval of hardliners.
In October, he asked police to be moderate when enforcing the hijab requirements and recently said, "We cannot take people to heaven by using whips," a remark that was condemned by conservatives.
Rather than wearing a full length traditional "chador" that drapes the head and body, many women wear a thinner head scarf, leggings and shirt.
Police in Tehran earlier this month launched a new drive against non-compliance of the female dress code. Officers were deployed on the capital's biggest roads, and women -- drivers and passengers -- checked.
The MPs letter and push for stronger enforcement coincides with an online campaign in which hundreds of Iranian women posted pictures of themselves flouting the dress code inside Iran.
The Facebook page "Stealthy Freedoms of Women in Iran," was launched by a London-based Iranian woman who said she wanted a debate on having the right to choose to wear the hijab. The campaign did not generate a reaction from the government.
At least two protests to demand enforcement of hijab have taken place in Tehran in the past two months.