The University of Auckland is launching a formal investigation after three Chinese men were filmed clashing with protesters on campus who were against a controversial proposed extradition bill in Hong Kong.

University student Serena Lee, 27 said she was left "shocked and shaken" after the men pushed her to the ground in front of a Lennon Wall at the city campus in Auckland on Monday evening.

Video of the scuffle between those supporting the bill and those against it has been uploaded on YouTube and shared on social media platforms.

Student from Hong Kong Serena Lee was pushed to the ground during an altercation with Chinese students at Auckland University July 2019 picture supplied still from video.

Lennon Walls, which lets people paste protests notes, have in recent weeks spread across Hong Kong and Lee said she had been given permission to put one up at the university.

A police spokesman confirmed it had also spoken to a complainant.

"We will be following up this incident and assessing the footage in due course," he said.

University spokeswoman Lisa Finucane said the video and notifications had been sent to the Vice-Chancellor and other senior members of the university.

"We are in touch with the students who have been involved and a formal investigation is underway," Finucane said.

She said the university had been made aware of recent disagreements and disputes between students who have different views over events in Hong Kong.

A proposed extradition bill would allow suspects in the Asian city to be extradited to mainland China.

The bill has been suspended, but demonstrators said they would continue with protests until it had been completely withdrawn.

Finucane said campus security had been briefed to ensure safety and security of those at the university would not be placed at risk.

She said the Vice-Chancellor also expected "all members of our community to abide by our commitment to academic freedom and freedom of speech".

Student from Hong Kong Serena Lee was pushed to the ground during an altercation with Chinese students at Auckland University July 2019 picture supplied still from video.

"While people may have different opinions on a matter, they must express those opinions in a manner that respects the rights and opinions of others," Finucane said.

"The university makes it very clear ... harassment, bullying, and discrimination are completely unacceptable."

Lee said some Hong Kong students at the university had been putting up the Lennon Wall when the three Chinese men accosted them.

In a video, one Chinese man was heard saying in Mandarin: "If you don't like China, get out of China!"

To which a Hong Kong student responded: "That's why we're in New Zealand."

Then another Chinese man continued speaking in Chinese, to which another Hong Kong student asked for it to be translated because he didn't understand Mandarin.

The man that told the student "you are not human, you are a f**king pig so you cannot understand human language."

Lee was then seen being pushed to the ground by one of the men during the scuffle.

"Physically, I am not injured, but inside me I am shocked and shaken," Lee said.

"The proposed law in Hong Kong could see the end of the city as we know it and our individual freedom, but I was stunned when people in New Zealand are also trying to shut down our freedom of expression."

Lennon Walls get their name from a wall in Prague that had been filled with John Lennon-inspired graffiti.

They first appeared in Hong Kong during the Occupy Protests in 2014 when thousands took to the streets to protest against China's decision to rule out fully democratic elections in the city.

Hong Kong, a former British colony, runs under a "one country, two systems" rule and has its own judiciary and separate legal system from mainland China.

However, critics fear the proposed new law would erode its independence.