China's foreign ministry has rejected claims by Google that Beijing is disrupting access to its e-mail service in the country.
"This is an unacceptable accusation," ministry spokeswoman Jiang Yu told a regular news conference on Tuesday.
Google said on Monday that difficulties faced by users of its Gmail service was the result of government blocks.
Users say the interference coincided with an internet campaign calling for protests like those in the Middle East.
Google said it had found no technical issues, and blamed "a government blockage carefully designed to look like the problem is with Gmail".
Last year, Google said it had suffered cyber-attacks from China-based organisations intent on hacking into the Gmail accounts of Chinese rights activists.
The incident caused tensions between China and the United States, and led to Google reducing its presence in the Chinese market.
Beijing has always denied any state involvement in the cyber-attacks, and has in the past called such accusations "groundless".