China's rubber-stamp legislature passed a wide-ranging new national security law Wednesday, officials said, as concerns grow that Beijing is enforcing ever-tighter limits on rights.

The National People's Congress standing committee passed the legislation by 154 votes to nil, with one abstention, officials said at the Great Hall of the People in Beijing.

Since President Xi Jinping came to power, China's ruling Communist Party has overseen a wide-ranging crackdown on activists, while unrest related to the mainly Muslim region of Xinjiang has worsened and spread.

"China's national security situation has become increasingly severe," said senior NPC official Zheng Shuna.

"We are under dual pressures from both the maintenance of national sovereignty, security and development interests while dealing with the external world and the maintenance of political security and social security, while dealing with internal society."

The law vows to "protect people's fundamental interests", the official Xinhua news agency said.

It had previously said the measure covers finance, science and technology, publications and education, and that China was mulling including "activities and assets in space, on the international sea bed and in polar regions".

Xi has made security concerns a top issue, and chaired the first meeting of the country's national security commission in April last year.

Beijing is embroiled in long-standing territorial rows in the East China Sea with Tokyo and in the South China Sea with several neighbours.