It followed the announcement of changes to student loans including increasing repayment rates, and the tightening of allowance eligibility including cutting allowances for people in post-graduate study.
However, IPCA chairman Judge Sir David Carruthers said there was no evidence to support various allegations of excessive force by police removing the blockaders.
Police had used "more active tactics" in the June 1 protest because they were aware of the event in advance and it was being held at the beginning of a long weekend, blocking the main route out of the city, Sir David said.
"The authority considers the police officers policing the protest behaved professionally despite being faced with verbal and physical provocation, including the demonstrators' kicking, punching, knocking off their hats, ripping off their epaulettes and pulling them into a hostile crowd," he said.
"It was only when the demonstrators sat down and blocked the southbound lanes of Symonds Street, causing obstruction and traffic disruption, that police took action against them."
He said video footage played in real-time on television news bulletins "does give the appearance that police used considerable amounts of force". However, when watched in slow motion the authority found police "used approved tactics", he said.
Those included open palm strikes and a thumb pressure technique to the neck, known as a mastoid grip, to remove protesters who had linked arms and were sitting in the middle of Symonds Street, Sir David said.
"The police were justified in removing the protesters and the force they used was proportionate, and no greater than was required, to achieve this purpose."
But demonstrator Guy Cohn said the lengthy two year process had led the students involved to "question the competency of the IPCA", criticising it for relying heavily on police evidence, which he said exaggerated the number and volatility of the protesters "to justify their over the top presence".
"The IPCA shows itself to be incredibly reluctant to criticise police behaviour, despite finding the police breached numerous protocols," he said.
"The IPCA has taken police claims at face value despite video evidence to the contrary, calling into question its independence and competency," Mr Cohn.
"This report raises significant issues around the competency of the IPCA, in terms of numerous inaccuracies and a failure to adequately address people's right to protest.
"Anyone who witnessed the protest will clearly see that the police response was unreasonable, violent, and disproportionate."
