A Dunedin protester who was dragged by the hair by a police officer is calling for better investigations into police misconduct.

Unite Union organiser Olive McRae was in Auckland taking part in a mass protest against the signing of the TPPA in February when the incident occurred.

Officer hauling protestor by her hair off motorway at cook street pic.twitter.com/Zp1758RFa2

— Lisa Owen (@lisaowennz) February 3, 2016

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It took place as small groups of protesters broke away from the main body of the march, and attempted to block roads and intersections around the Auckland CBD.

McRae said she filed a complaint with the Independent Police Conduct Authority. However, she said the complaint was then handed over to the police to investigate themselves.

"For them to investigate themselves, and find that what he did was wrong, but tell me that they're not going to say if they're going to do anything about it, and that they're not going to tell me who this man is - it makes me really uncomfortable."

PHOTOS: TPP signed in Auckland February 4 2016

McRae said the training of the officer in question was inadequate.

"The training that led up to that day, which the Police took part in, he was not involved in that, so he should never have been on the front line and this is clearly the reason why."

She said the event has scarred her - but she will continue to protest.

"Protesting in New Zealand is a big part of our democratic process, and it has been for a long time and I hope that it continues to be." In February, Superintendent Richard Chambers said no unnecessary force was used by police, despite photos depicting McRae being dragged by her hair, and a man being pushed back by his throat.

He said some protestors endangered themselves by attempting to run onto the motorway and actions taken by police were in the interest of public safety.