The United Nation's human rights chief has voiced concern over heavy-handed steps to remove protesters from university campuses in the United States where pro-Palestinian demonstrations have been taking place.

The statement comes as dozens of helmeted police on Tuesday night marched onto Columbia University in New York City – the epicentre of the student protests – and began evicting a building that had been barricaded by pro-Palestinian student protesters.

“Freedom of expression and the right to peaceful assembly are fundamental to society – particularly when there is sharp disagreement on major issues,” UN High Commissioner for Human Rights Volker Türk said in a statement.

It continued by saying that many of the protests have been held without incident and that at a number of locations, they have been dispersed or dismantled by security forces.

Hundreds of students have been arrested, while others face charges or academic sanctions, the statement said, adding that enforcement actions by universities or law enforcement to restrict such expression "need to be carefully scrutinised".

The statement continued by quoting Türk as saying: “I am concerned that some of [the] law enforcement actions across a series of universities appear disproportionate in their impacts."

The demonstrations – the most sweeping and prolonged unrest to rock US college campuses since the Vietnam war protests of the 1960s and 70s – have posed a challenge to university administrators trying to balance free speech rights with complaints that the rallies have veered into anti-Semitism and hate.

The unrest has swept through US higher education institutions like wildfire, with many student protesters erecting tent encampments on campuses from coast to coast.

Footage of police in riot gear summoned at various colleges has been viewed around the world. (Additional reporting by AFP)