Iranian news agencies recently quoted Tehran prosecutor Said Mortazavi as saying those behind irreligious and immoral websites would be "harshly confronted."
The prosecutor's office has set up a special department to deal with Internet "crimes." Mortazavi said a team of Internet experts along with two officials would identify and block websites that "do not follow religious principles and are immoral."
RFE/RL's Radio Farda has reported that intelligence services would also take part in the campaign.
Earlier this month, Esmail Jafari, a blogger from the southwestern city of Bushehr was sentenced to five months in prison. He was found guilty of antigovernment publicity and disseminating information abroad.
According to Reporters Without Borders, a Paris-based media rights groups, at least two online journalists, Mojtaba Lotfi and Shahnaz Gholami, are currently being detained in Iran.
Gholami, an editor of the "Azar Zan" blog, was charged with jeopardizing national security.
In October, an adviser to Iran's chief prosecutor said more than 5 million antisocial and immoral websites have been blocked and are no longer accessible in the country.
Most recently, an Iranian dating website, "Hamsarchat," was fined and banned after being accused of promoting prostitution.
The popular website, which claims to be "Iran's most complete spouse-finding website," has been taken to court following a complaint from Tehran's public prosecutor.
Growing Internet Presence
With some 20 million people with access to the Internet, Iran is one of the biggest Internet users in the Middle East. And despite all the blocks, filtering, and other restrictions, blogging is becoming increasingly popular.
According to media reports, there are some 65,000 bloggers in Iran, most of whom try to stay away from political issues, focusing instead on social, art, family, and other safer topics.
But the popularity of the Internet, especially, among young people, and its impact on society is obviously a source of concern for the Iranian authorities.
Some Iranian leaders have warned that the West is trying to provoke a "Velvet Revolution" in Iran using the Internet.
Alongside Iranian music, news, and political websites, they have also blocked access to popular foreign sites such as YouTube and Facebook.
However, according to Said, a blogger in Tehran, the authorities' "old method of filtering is not working anymore." Said tells Radio Farda that "with simple software or proxies, you can avoid any filter."
In the meantime, Iran's authorities and religious leaders are themselves trying to use the Internet to get their message out.
From clerics in the holy city of Qom to President Mahmud Ahmadinejad, they have set up personal websites to promote their ideas to the public.
RFE/RL's Radio Farda contributed to this report