The Independent Police Complaints Authority has confirmed it is investigating claims of police brutality made by a group protesting against the Budget.
The group blocked Auckland city traffic on Budget day on 24 May, and again a week later.
The group says its complaint to the Independent Police Complaints Authority addresses the use of what it says was excessive use of force, and the lack of identification of some police officers.
Spokesperson Brendon Steen was surprised by the way the police acted.
"The week before they'd been understanding, they'd accommodated it. On the day of the first (of June) we'd had a conversation with them; one of their liaison officers had come up and spoken to us about what we were going to do and how we were going to work.
"So it came completely out of the blue for us - they were grabbing random people ... there's no discernible motive for acting the way that they did."
Students just want attention - police
Police Association president Greg O'Connor says he believes the protesters are just using the complaint as a way of getting more attention.
"I'm confident that police in this situation did what they needed to do to ensure that those who were being inconvenienced by the protest were able to get on with their life.
"Of course police have to act reasonably, in my experience they do - generally- and
where complaints are made at the end it's often a continuation of the whole protest activity."
At least 20 people were taken away by police during the protest in Symonds Street, central Auckland, on 1 June.
The students said they opposed changes to student allowances in the 2012 budget, which penalised already struggling students.