The university has rejected those claims and vice-chancellor Michael Spence has defended the 2 per cent pay rise being offered to staff, saying that Sydney is "not a rich university." Dispute: A demonstrating University of Sydney student is dragged from the lecture hall by police. Credit:@honi_soit The altercation with police occurred after a group of protesters entered a chemistry lecture hall about 10am on Tuesday. "We were in the lecture hall chanting and trying to stop the class, because that lecturer had decided to work on the strike day and undermine the campaign," said student protester Tom Raue. "Riot police came in the [back] and started dragging people out of the of the lecture hall."

Mr Raue said the protesters were behaving peacefully, and that the police actions were overly aggressive. "I got punched in the face by a riot cop and my shirt was ripped," he said. But another student, who gave her name as Emily, told Fairfax Radio the protesters were fighting the police. "The police had to come in and then the demonstration just got out of hand and you had the demonstrators fighting the police," she said. Footage posted online by student journalist Adam Chalmers shows a group of protesters chanting and playing the drums entering the chemistry lecture while the strike was taking place.

Police charged two of the protesters – a 31-year-old man from Stanmore and a 33-year-old woman from Newtown – with resisting arrest, while the man was also charged with assaulting police. A third woman was issued with a field court attendance order for assaulting police, resisting arrest and offensive language. The other two people were released. A spokesman for the university said all five had been banned from campus for the remainder of the industrial action. Of the five arrested, two were students from the university and the other three were neither staff nor students, according to the spokesman. NTEU branch president Michael Thomson said the picket would continue on Wednesday as planned. "We had a peaceful picket, we welcome the support of everybody and we understand why people are angry," he said.

Staff voted to take the strike action over an ongoing dispute over their new Enterprise Bargaining Agreement. Professor Raewyn Connell, from the Faculty of Education and Social Work, wrote an open letter to management this week condemning what she said was growing staff-to-student ratios, increasing micro-management and surveillance and changes proposed in the latest agreement. "On some points, management proposed startling increases in managerial prerogative, and weakened accountability by management to staff. On a number of points the proposal erodes existing protections for staff," she said. The union says more than 40 per cent of teaching at the university is now performed by casual academics. That claim has been rejected by the university, which says the percentage of academic staff employed on a casual basis has decreased by 4.8 per cent since 2001.

In response to Professor Connell's letter, vice-chancellor Michael Spence said the university was bargaining in good faith and that 18 amendments had already been made to their original proposal. But he said said the university's finances were not what they had once been. "We are not a rich university," he wrote in an open letter of his own. "The institution at which I arrived had significant financial problems, and a long-term commitment to improving facilities for staff and students ... we must find a salary settlement that allows us to meet the competing needs of staff for appropriate pay, conditions and facilities." In a statement, deputy vice-chancellor Stephen Garton also rejected union claims about the growing casualisation of the workforce and worsening staff-to-student ratios.

“The university is offering greater choice and flexibility for staff to meet their needs in exchange for the removal of some conditions that are too inflexible in the working context of a modern university,” Professor Garton said. “The University of Sydney does support a modest pay rise for staff but regrettably the union's pay proposals are unrealistic. If we were to meet the demands for 7 per cent pay rise, it would cost the university $35m more next year than the 2 per cent rise proposed by the university.”