BEIJING, March 31 -- Internet hackers doubled the number of attacks on Chinese government websites in 2005 over the previous year, figures from the National computer Network Emergency Response Technical Coordination Center of China show.

Hackers targeted government websites amounted to 2,027 times, one sixth of the 13,000 attacks, in China last year, Professor Du Yaojin, an engineer of the center, said.

"Disguised tampering, such as attacks by Botnet, was not included in the statistics," Du added.

Botnet is a network of automatic, or "zombie" computers, that can harness their collective power to do considerable damage or send out huge amounts of junk e-mail by professional hackers after receiving commands from overseas operator or servers.

China has more than 1,200 government websites and three quarters of Chinese counties have opened their own government websites.

"Without efficient security and emergency response systems, leaking of important information is quite possible, which limits the development of e-government of China," said Du.