Thousands of students at a central China university continued to stare down police on Tuesday as they maintained a boycott of classes over their treatment by school management.

Students have been on strike since between 5,000 and 10,000 of them began ransacking the campus on Thursday night, with several hundred police brought in to quell the unrest, according to witnesses and participants.

Photos posted on the Internet from Zhengzhou University in Henan province showed an on-campus bank branch, dormitories and cars had been vandalized, while chairs had been torched and bicycles strewn across the grounds.

The students, from the university's Shengda Economics, Trade and Management College, said they were protesting because they had been misled into believing they would get diplomas bearing the name of Zhengzhou University.

However they were later told they would only get diplomas from the less prestigious college affiliate.

The violent scenes lasted into the weekend, with several thousand students continuing to demonstrate peacefully around the campus administration building on Tuesday, according to one of the participants surnamed Xu.

"The stance of the school remains tough but if the institute does not resolve this issue, we will continue to boycott classes and examinations," Xu said.

"Some students have been beaten. They also beat journalists and confiscated cameras."

Xu said several hundred police wearing anti-riot gear had refused to allow the students off the college campus.

Although there were no scenes of violence on Monday and Tuesday, students said they would continue to boycott their classes and refuse to sit upcoming exams until their dispute was resolved.

"Things are continuing to develop. Today there are more students boycotting classes and refusing to take final exams," one student surnamed Liu told AFP on Tuesday.

Students have said the issue had festered since 2003.

Liu on Monday told AFP the university had been "treating us badly for many years." "We couldn't bear it any longer," he said.

Local police and Communist Party officials refused to comment Tuesday on the incident, while state controlled media were also silent, reflecting the ultra-sensitive nature of student unrest in China.

College administrators also refused to comment.

Internet chatrooms that listed unrest on the campus as a topic, were not accessible within China and appeared to be blocked by the country's web censors to prevent news of the protests from circulating.

Student protests have long been a barometer of overall social unrest in China, with university demonstrations often spilling over into the larger community.

Students led the 1989 Tiananmen democracy demonstrations, which were eventually brutally suppressed by the military with hundreds, if not thousands, of people killed.