The hacking collective claimed responsibility for defacing 485 websites in the territory, replacing them with a message urging users to take action against government tracking and censorship.
"Hello, we are Anonymous. All these years the Chinese Government has subjected their people to unfair laws and unhealthy processes. People, each of you suffers from tyranny of that regime," Anonymous wrote.
Numerous government websites and trade groups were among those hit, according to a post on Pastebin. A message on Anonymous's Chinese Twitter account also confirmed the attacks.
Chinese news services are reporting that the government denied any cyber attacks took place, despite Anonymous posts remaining online for some time, The Telegraph understands.
Last summer, several key figures from Anonymous were arrested in the UK, Ireland and the US as part of a global crackdown against the collective. This was followed by arrests in Argentina, Chile, Columbia and Spain.
Anonymous has targeted the Catholic church, Sony and The Sun newspaper in the past.