Students have staged a protest against a coronavirus lockdown at a university in eastern China as authorities across the country take baby steps away from their hardline zero-Covid policy.

Millions of people around China still face restrictions, despite some cities rolling back mass testing and curbs on movement following nationwide anti-lockdown protests last week.

Analysts at Japanese firm Nomura on Monday calculated that 53 cities -- home to nearly a third of China's population -- still had some restrictions in place.

China's vast security apparatus has moved swiftly to smother the demonstrations, deploying a heavy police presence while boosting online censorship and surveillance.

But videos published on social media Tuesday and geolocated by AFP show a crowd of students at Nanjing Tech University on Monday night shouting demands to leave the campus.

"Your power is given to you by students, not by yourselves," one person can be heard shouting in the footage. "Serve the students!"

A third-year student who asked to remain anonymous confirmed the protest took place, a day after the school announced it would seal off the campus for five days because of just one Covid case.

Chinese universities have restricted movement for months, with many requiring students to apply for permission to leave the campus and banning visitors.

The Nanjing Tech student told AFP her peers were unhappy about poor communication from the university and worried they would be blocked from travelling home for the winter holidays.

In the footage, the crowd can be seen arguing with university representatives and shouting for school leaders to step down.

"If you touch us you will become the second Foxconn!" one protester yells in reference to violent demonstrations last month in central China at a factory run by the Taiwanese tech giant that supplies Apple.

Other clips showed a police car arriving on the scene and university officials promising students they would compile their complaints in a file.

The Nanjing protest comes days after people took to the streets in multiple Chinese cities urging an end to the zero-Covid policy, with some even calling for Chinese President Xi Jinping to step down.

Hundreds gathered at Beijing's elite Tsinghua and Peking universities at the end of last month as well as campuses in the cities of Xi'an, Guangzhou and Wuhan.

Authorities have cracked down on subsequent efforts to protest while appearing to answer some demands by easing a number of restrictions.

On Tuesday Beijing said offices and commercial buildings including supermarkets would no longer require visitors to show proof of a negative test.

A host of other cities including Shanghai have also dialled down mass testing mandates in recent days.