Prime Minister Tony Abbott is behaving like a coward by cancelling his visit to a university amid nationwide protests, a student union says.

Mr Abbott and his Education Minister Christopher Pyne were due to visit a Geelong research facility at Deakin University today, but called it off after federal police raised concerns about their personal safety.

The visit was to have coincided with a national day of student protests against the government’s higher education reforms, including removing caps on fees universities can charge.

National Union of Students president Deanna Taylor says Mr Abbott must explain why he’s worried about facing students and answering their questions.

“I think the prime minister and his ministers are being a bit cowardly and trying to portray students as though they’re violent rabble-rousers who are out to cause trouble, which isn’t the case at all,” she told AAP.

“They’re trying to make us sound like spoiled little brats who don’t know how good we’ve got it. They have a very clear agenda.”

We shouldn’t basically be penalising people for getting a higher education.

Ms Taylor said an expected 2000-strong rally in Melbourne would be the nation’s biggest, but thousands more would rally across the country in all capital cities except Darwin.

Government plans to deregulate fees would burden students with debt for 30-40 years and hinder them from buying a house or car, she said.

“We shouldn’t basically be penalising people for getting a higher education,” she said.

In the past week, protesters at Sydney and Melbourne universities have come under fire for heckling Foreign Minister Julie Bishop and former federal Liberal MP Sophie Mirabella.

But Ms Taylor says students are so incensed by the proposed changes they are doing what they can to get their point across.

“Not all students have access to the corridors of power and can’t go and lobby politicians,” she said.

“For a lot of students who are disenfranchised, protesting and demonstrating is really their only way of voicing their discontent.”

Mr Pyne said it was the prime minister’s decision, in conjunction with his office, to call off the Geelong visit after receiving the police brief.

“(He thought) it would be wiser to not go and create that tumult at Deakin so students can get on with their studies unmolested by the Socialist Alternative, which seem quite intent on shutting down democracy in Australia,” Mr Pyne told the ABC.

Socialist Alternative is a far-left wing organisation that publishes the Red Flag paper.

He criticised protesters for complaining about having to contribute more to their own education and accused them of seeking to shut down democracy.

Sad day for democracy?

Victorian Premier Denis Napthine as well as Labor and Greens MPs are still expected to visit the university.

“I think it’s a sad day for Australian democracy that the Prime Minister can’t attend important events in our country because of the threatening behaviours of a small minority,” Mr Napthine said.

“People are free to protest in Victoria and Australia, we are a democracy, but they must behave, act within the law and allow others to go about their lawful business, including the prime minister of the country.”

Reason to protest

Deputy Leader of the federal Opposition Tanya Plibersek said students had a reason to protest.

The deregulation of university fees would mean poor kids wouldn’t make it to university and would be denied a successful career, she said.

“This will take us to a two-tier American-style university system where the best courses and the best universities are completely unaffordable to ordinary people,” she told ABC radio.

But she condemned the protests against Ms Mirabella and Ms Bishop and said students should rally in a peaceful and democratic manner.

Labor frontbencher Richard Marles, whose electorate covers Geelong, said he was disappointed Mr Abbott had missed an opportunity to meet with workers affected by Alcoa’s decision to close its Point Henry aluminium smelter.

“We have not seen the prime minister go anywhere near an Alcoa worker,” he told Sky News.

Other students hit back on social media.

I’d not be proud of not showing up at the University, Christopher Pyne. Stop being a wimp. The students aren’t going to hurt you. #auspol

— Henry Beans (@HenryBeans) May 20, 2014

The irony of uni student thug Tony Abbott too scared to walk into a university #auspol

— Jack Flack (@Jackflack67Jack) May 20, 2014