China has shut down websites, made a string of arrests and punished two popular microblogs after rumours of a coup linked to a major scandal that brought down a top politician.

Authorities have closed 16 websites for spreading rumours of "military vehicles entering Beijing and something wrong going on in Beijing," Xinhua news agency said, citing a spokesman with the State Internet Information Office (SIIO).

The spokesman said that two popular microblog sites also had been "criticised and punished accordingly".

The March 15 ouster of Bo Xilai as party chief of the inland city of Chongqing, who was linked to a scandal involving a senior aide, has shaken China's communist party as it readies for a top leadership change later this year.

After he was sacked, popular microblogs, including those run by Sina and Tencent, were awash with speculation about a government coup.

Xinhua says Sina and Tencent have shut the comment functions on their popular microblog sites from March 31 to April 3 to "clean up rumours and other illegal information spreading" through the site.

On Saturday, Sina's Weibo users could still make posts, though other users could not respond.

Beijing-based microbloggers had previously been ordered to register their real names by mid-March or face unspecified legal consequences.

In another sign of the state's tight policing of the web, Xinhua said 1,065 people had been arrested since February 14 during an operation in Beijing to combat internet crime.

More than 3,000 websites had also received warnings after police targeted the smuggling of firearms, drugs and toxic chemicals, and the sale of human organs and personal information online, Xinhua said.

In an editorial, the People's Daily, the mouthpiece of the Communist Party, pledged to punish those responsible for the "lies and speculation".

"Online rumours undermine the morale of the public and if out of control, they will seriously disturb the public order and affect social stability," said the newspaper.

AFP/Reuters