Sam Gyimah, the Universities Minister, has warned of a “creeping culture of censorship” on university campuses.
Mr Gyimah told the Human Rights Committee inquiry into free speech that a culture of intolerance was spilling over from social media.
He said that “mollycoddling” students so they did not discuss controversies was another form of censorship.
But Harriet Harman, who chairs the committee, questioned whether there was evidence of free speech being eroded.
Concerns about threats to free speech in university had been widely publicised, but that was not the same as providing evidence, she said.
Mr Gyimah said he thought there was a growing problem in universities of groups trying to stop others from expressing ideas – although specific evidence could be “difficult to gather”.
He said there had been protests over speakers on topics such as Israel and issues of religion, sexuality or political belief.
Last week, Jacob Rees-Mogg faced a protest when he spoke to students at the University of the West of England – and the Conservative MP will be giving evidence to the committee later on Wednesday.
There have also been concerns over “no-platforming”, where people are prevented from speaking – but members of the committee pressed Mr Gyimah over whether there was any proof of this being a widespread problem in universities.
The committee is also considering whether the Prevent counter-extremism strategy stops students from discussing some controversial subjects.
Ben Wallace, Security Minister, said there was “no real evidence of free speech being curtailed by Prevent”.
“We have struggled to find evidence of actual events that have been cancelled.”
But Mr Wallace said: “Freedom of speech is not absolute.” For example, it was not lawful to incite racial hatred.
He said that Prevent was a response to an authentic problem, of people being radicalised on campus.
Radical Islamists were still recruiting in “educational settings” and 23,000 people in the UK were currently considered security concerns with an “extremist mindset”, he told the committee.
But MPs and peers on the committee questioned whether there was enough guidance to make a clear distinction between legitimate, strong views and unlawful violent extremism.
They raised concerns that even if events had not been cancelled, there could have been events that were never even proposed, because of fears over being referred to Prevent.
In December, the previous Universities Minister, Jo Johnson, warned that universities that failed to uphold free speech could face fines from the new regulator, the Office for Students.
He said “no-platforming” was stifling debate and that universities should “open minds, not close them”.
Earlier this week, the Prime Minister, Theresa May, said: “In our universities, which should be bastions of free thought and expression, we’ve seen the efforts of politicians and academics to engage in open debate frustrated by an aggressive and intolerant minority.
“It’s time we asked ourselves seriously whether we really want it to be like this.”