Turkey has blocked a Google service used by Turks to circumvent a ban on Twitter, Turkish newspapers said, as Prime Minister Recep Tayyip Erdogan's government defended its social media clampdown.

The government has prevented access to Google DNS, the newspapers reported. To use Twitter, Turks had turned to DNS, which was created in the 1980s to help computers find websites using words instead of numbers. Calls to Mr Erdogan's office and the country's telecommunications watchdog went unanswered on Saturday.

Social media clapdown: Prime Minister Recep Tayyip Erdogan. Credit:AP

"Preventive measures" against Twitter were taken in response to its defiance of hundreds of court rulings, Mr Erdogan's office of public diplomacy said. "Twitter has been used as a means to carry out systematic character assassinations by circulating illegally acquired recordings, fake and fabricated records of wiretapping."

Turkey has said it will lift restrictions on Twitter when the company complies with the nation's requests. Twitter suspended an adult-content account today, reacting to a Turkish request, state-run Anatolia news agency said.