Google stopped censoring search results on 22 March
Google has said that a problem that meant that Chinese users of its service were unable to access search results on 30 March was due to a technical error.
Many reports had speculated that the block may have been put in place by the Chinese government.
Earlier this month Google stopped censoring its search results in China in defiance of the government.
The company now redirects Chinese users to the uncensored pages of its Hong Kong website.
A spokesperson for the firm said that "lots of users" had been unable to access the Hong Kong site today.
"This blockage seems to have been triggered by a change on Google's part," the spokesperson said.
The firm said that in the last 24 hours the letters "gs_rfai" started appearing in the URLs of Google searches globally.
"The great firewall was associating these searches with Radio Free Asia, a service that has been inaccessible in China for a long time -hence the blockage," said the spokesperson.
"We are currently looking at how to resolve this issue."
Google first outlined its plans to stop censoring search results on 12 January after it revealed that it had been targeted in a sophisticated cyber attack thought to originate in China.
The attacks - which also affected 20 other companies - were thought to target the e-mail accounts of human rights activists.
After weeks of negotiations, the firm finally stopped censoring results on the 22 March.