The Committee to Protect Journalists says Turkey's slide into internet authoritarianism shows why it is the "leading jailer of journalists worldwide".
Turkish MPs have adopted new internet legislation roundly criticised as a fresh assault by Prime Minister Recep Tayyip Erdogan on freedom of expression, access to information and investigative journalism.
The proposals come amid parallel moves by Erdogan to push through contentious judicial reforms as he fights to keep the lid on a deeply damaging corruption probe entangling some of his closest allies.
After hours of debate, during which opposition MPs blasted the bill as "censorship", the measures were adopted in the chamber, where Erdogan's ruling Justice and Development Party (AKP) dominates with 319 of the 550 seats.
The bill extends what are already hefty internet curbs in place under a controversial 2007 law that earned Turkey equal ranking with China as the world's biggest web censor according to a Google transparency report published in December.
The text notably permits a government agency, the Telecommunications Communications Presidency (TIB), to block access to websites without court authorisation if they are deemed to violate privacy or with content seen as "insulting".
Yaman Akdeniz, law professor at Bilgi private university in Istanbul, said the powers given to the TIB were "Orwellian".
This body will also be able to request users' communications and traffic information from hosting providers - obliged to retain up to two years' worth of data - without a court order, Akdeniz said.
The measures, Akdeniz said, will "move Turkey away from the European Union in terms of internet policy, perhaps a few steps closer to China", where the web is heavily censored by the communist authorities.
At the start of the debate, opposition lawmaker Hasan Oren had harsher words, comparing Erdogan to Hitler.
"When you came to power you talked of enhancing democracy in Turkey, Now you are trying to implement fascism," Oren said.
"Remember that Adolf Hitler used the same methods when he rose to power."
The amendments, which form part of a so-called omnibus bill containing a mishmash of other measures, add to an already draconian approach under the 2007 law.
Under that existing legislation, websites including blogging tool Wordpress and video-sharing services DailyMotion and Vimeo have been blocked temporarily by court orders, while YouTube was off limits for two years until 2010.
Reporters Without Borders said the aim is "to reinforce cyber-censorship, government control of the internet and surveillance".
The Committee to Protect Journalists (CPJ) called it a "slide into internet authoritarianism" in a country that is the "leading jailer of journalists worldwide".