China's has passed sweeping new legislation reinforcing government controls over cyberspace in the wake of what it called growing threats to Chinese networks.

The vaguely worded National Security Law adopted Wednesday calls for strengthened management over the web and tougher measures against online attacks, theft of secrets, and the spread of illegal or harmful information.

It said core information technology, critical infrastructure and important systems and data must be "secure and controllable" in order protect China's sovereignty over its cyberspace.

China says it is a major target of hacking and other cyber-attacks, while the ruling Communist Party has expended vast efforts in blocking content available in China deemed subversive or illegal.

China is also accused of running a state-sponsored effort to hack computers and steal government and commercial secrets overseas.