Turkey's parliament has approved internet controls enabling web pages to be blocked within hours in what the opposition decried as part of a government bid to stifle a corruption scandal with methods more suitable to "times of coups".

Under a bill passed late on Wednesday, telecommunications authorities can block access to material within four hours without a prior court order, tightening restrictions imposed in a widely criticised law adopted by the EU candidate in 2007.

Social media and video sharing sites have been awash with alleged recordings of ministers including Prime Minister Tayyip Erdogan and businessmen close to him, presented as evidence of wrongdoing. Reuters has been unable to verify their authenticity.

"This is against the constitution. Bans like this exist in times of coups and have not been able to conceal any corruption," Umut Oran, a deputy from the main opposition CHP, told the general assembly.

Erdogan's critics say his response to the corruption scandal is further evidence of the authoritarian tendencies of a man long held up by the West as a potential model of democratic leadership in the Muslim world. The Turkish lira has fallen sharply amid the political uncertainty.

The internet legislation, which still needs the approval of President Abdullah Gul, will also allow for the storage of individuals' browsing histories for up to two years, and was roundly attacked by opposition MPs.

The scandal erupted on Dec. 17 with the arrest of businessmen close to Erdogan and three cabinet ministers', sons and has spiralled into one of the greatest threats to his 11-year rule, months ahead of local and presidential elections.

Erdogan has portrayed the scandal as an attempt by a U.S.-based cleric with influence in the police and judiciary to undermine him in the run-up to local and presidential elections. The cleric, Fethullah Gulen, denies the accusation.

His government has responded by purging the police and judiciary, reassigning thousands of officers and dozens of prosecutors. It says Gulen's Hizmet movement represents a challenge to legitimate, democratically elected government.

Erdogan has won three elections in a row since his AK party was first voted to power in 2002. Local polls next month will provide a test of whether his popularity will hold up, or even grow, amid the graft scandal and power struggle with Hizmet.

The government says the reforms, sent to parliament before Dec. 17 but broadened in recent weeks, are aimed at protecting individual privacy not gagging its critics.

"The latest regulations are not censorship and are not a ban," AK Party deputy Necdet Unuvar said in comments on his personal website. "They are regulations needed to protect the confidentiality of private life."

TIGHT RESTRICTIONS

Turkey already has strict Internet laws under which thousands of websites have been blocked, from news portals viewed as close to Kurdish militants to gay dating sites.

More than 40,000 sites are blocked, according to Turkey's engelliweb.com, which tracks access restrictions.

The 2007 law prohibits insults to modern Turkey's founder Mustafa Kemal Ataturk as well as the encouragement of suicide, sexual abuse of children, the supply of illegal drugs, promotion of prostitution, and unauthorised gambling.

Access to the video sharing site YouTube was blocked between 2008 and 2010 because it hosted content viewed as insulting Ataturk, who founded the modern secular republic just over 90 years ago.

Under the new law, decisions to remove material taken by the telecoms authority (TIB) will be subject to judicial review and a court will rule within 24 hours. TIB will be able to appeal.

"This reform proposal ... gives the powers of the legislative, executive and judiciary completely to the TIB, which is turning into an intelligence agency," two professors from Istanbul's Bilgi University and Ankara University said in a report this week.

"From the perspective of fundamental rights and freedoms it indicates the start of a period of great darkness," professors Yaman Akdeniz and Kerem Altiparmak wrote.

Parliament, where Erdogan's AK Party has 319 of 550 seats, voted in favour of the articles but the wider reform package of which they are part has not yet been adopted as a whole. It is expected to pass later on Thursday.

Ahead of the adoption of the articles, the Committee to Protect Journalists' internet advocacy coordinator Geoffrey King said the changes to an already restrictive Internet law would "compound a dismal record on press freedom".