The paper claims that the timing of the attacks coincided with the reporting for a Times investigation, published online on Oct. 25, that found that the relatives of Wen Jiabao, China's prime minister, had accumulated a fortune worth several billion dollars through business dealings.
China's foreign ministry dismissed the accusations.
"To arbitrarily assert and to conclude without hard evidence that China participated in such hacking attacks is totally irresponsible," said spokesman Hong Lei.
"China is also a victim of hacking attacks. Chinese laws clearly forbid hacking attacks, and we hope relevant parties takes a responsible attitude on this issue."
According to the paper, the attackers installed malware that enabled them to gain entry to any computer on The Times's network. The malware was identified by computer security experts as a specific strain associated with computer attacks originating in China. More evidence of the source, experts said, is that the attacks started from the same university computers used by the Chinese military to attack United States military contractors in the past.
Security experts found evidence that the hackers stole the corporate passwords for every Times employee and used those to gain access to the personal computers of 53 employees, most of them outside The Times's newsroom. No customer data was stolen from The Times, security experts said.
The Wall Street Journal also says that its computer systems have been subjected to ongoing attacks from hackers based in China, for the apparent purpose of monitoring the newspaper's China coverage.