Chinese authorities appear to have severely disrupted the WhatsApp messaging app in the latest step to tighten censorship as they prepare for a major Communist Party congress next month.

Users in China have reported widespread disruptions in recent days to the Facebook-owned service, which had previously malfunctioned in the country over the summer.

Experts said the problems began on Sunday, although text messages, voice calls and video calls appeared to be working again on Tuesday, though voice messages and photos were not going through.

WhatsApp provides message encryption technology that likely does not please Chinese authorities, which closely monitor and restrict cyberspace through their "Great Firewall".

Many Chinese activists favour WhatsApp over local messaging apps because of its end-to-end encryption function.