The protests that have gripped Hong Kong have spilled over into Australia in recent weeks, with domestic and international students showing support for the city's pro-democracy movement. Counter-protests by nationalist Chinese students have resulted in tense and sometimes violent confrontations.

Liberal MPs have started to speak out about their concerns after Hong Kong and pro-democracy students complained of threats, monitoring and harassment. The Sydney Morning Herald and The Age revealed one student's account of his family in China being approached by authorities after he participated in an event in Brisbane.

Mr Tehan said the "right to free speech and to peaceful and lawful protest is protected in Australia, even on contentious and sensitive issues". He said a strong belief in freedom of speech was why the government commissioned former High Court chief justice Robert French to review the protections in place in Australia.

He said the model code proposed by Mr French outlines that "freedom of speech is a paramount value of universities", academic freedom is their "defining value", and the importance of institutional autonomy.

"As Mr French stated: Universities have a 'duty to ensure that no member of staff and no student is subject to threatening or intimidating behaviour by another person or persons on account of anything they have said in exercising their freedom of speech'," Mr Tehan said.

He "strongly" urged universities to implement the code and welcomed that some were already moving in that direction.

With large cohorts of international students in Australia, the Hong Kong protests have triggered tensions at universities across the country, including the University of Queensland, the Australian National University, the University of Sydney, the University of Tasmania and Monash University.

Much of the friction has revolved around the "Lennon Walls" set up on campuses by students in support of protesters in Hong Kong. Chinese students have been caught destroying the installations and harassing students contributing to them.

Universities have moved to protect the displays, stationing security guards nearby around the clock and condemning attempts to undermine free expression.

Kevin Carrico, a senior lecturer in Chinese studies at Monash University, said statements about free expression needed to be backed up with practical action because "students from Hong Kong are more scared to protest on Australian campuses than they are in the emerging police state" they come from.

"In reality, there have been a series of cases of people being actively intimidated and threatened, even for silent, peaceful protests. I witnessed such intimidation, threats to report people to the [People's Republic of China] consulate, and even vague death threats a few steps away from my office at Monash's Clayton campus," he said.

"And this intimidation has been cheered on by the PRC consulate, which clearly has no respect for rights nor for Australian sovereignty."

Dr Carrico said a "clear line needs to be drawn", with real consequences for any attacks on important freedoms on campuses.

Liberal MPs have added their voice to a chorus of concern about the risk of undue influence and interference at Australian universities, warning that academic and democratic values must be prized.

Victorian senator James Paterson said recent protests against the proposed extradition bill in Hong Kong highlighted his long-standing fears.

"Our universities must understand their obligation to ensure the values we espouse as a nation are upheld on campus too, including free speech, the right to protest and academic freedom," he said.

Queensland senator Amanda Stoker hit out at a "crisis of leadership" at universities and said they deserved to face questions about how much influence the Chinese government has.

Sydney MP and former diplomat Dave Sharma said he fears some universities "have become a little too dependent on foreign university students" for revenue and Victorian MP Tim Wilson said Australia should "keep a watchful eye that universities not become a vehicle for foreign governments to exercise soft influence in Australia".

The tensions over Hong Kong have emerged amid a broader debate about academic freedoms in Australia, with universities considering how to implement the code proposed by Mr French earlier this year.