The complaints, dating back to 2009, include allegations that may constitute student-to-student sexual harassment.

Mother of five Jessie-Lee Nolan said an incident earlier this year - where her son was left "shaking and crying" - was the last straw and forced her to remove her children from the school.

Ms Nolan said her son had fallen off his bike when a boy "grabbed [her son] by the mouth and slammed him onto the concrete pavement and he hit the back of his head."

Ms Nolan said she had contacted the police over the incident and said it took the school more than two weeks to respond. She said she was then told by the school that the matter was being investigated and the other child was receiving counselling.

Earlier in 2013, Ms Nolan said one of her daughters was "grabbed" in the genital area by another student. "They didn't even call me for four days after that. It happened on the Thursday, and it wasn't until the Tuesday that the school rang me," Ms Nolan said.

Ms Nolan said she first contacted the ACT Education and Training Directorate in 2011, when her son was in Year 1 at the school and came home with cut hair and clothes. Ms Nolan said the directorate then assigned an assistant to the class for a short period, but the bullying continued.

Ms Nolan then took the matter to the Minister for Education, Joy Burch, via email in March this year. It is understood the directorate contacted the parent that day and started to arrange for the children to move schools.

A spokeswoman for Ms Burch said she was "disappointed that for this family the outcome was to change schools. I am pleased, however, that the Directorate was able to make the change happen in the best interests of all concerned". The directorate has said it does not comment on individual cases.

Ms Nolan said she was "very happy with the new school but it's unfair that we were forced to go outside our area".

Current Palmerston parent Susan Hodgkinson said she was not informed promptly of a number of serious incidents.

"I feel sick dropping him off every morning as I don’t know he’s safe. I’m frustrated and I don’t know what to do, it’s not fair that we should have to move," Ms Hodgkinson said.

Kristen Barbaro, who pulled her daughter out of the school in 2012, said the school’s “bullying policy is that it gets brushed off".

Another former Palmerston parent who did not want to be named said her daughter was threatened by a male student who said he would bring in a knife and "slash her like a pig". She said she thought her complaints were "washed under the carpet".

Kara Lesley Mills' son attended the school in 2009. Ms Mills said one afternoon she noticed "deep scrapes all the way up [her son's] body and he said he and another child at the school had an argument and the boy dragged him along the ground." Ms Mills said she was unsatisfied with the school's response and decided to pull him out of the school.

A spokesman for the ACT Education and Training Directorate said "Palmerston Primary School regularly emphasises the values of the school through assemblies and in class activities."

The directorate spokesman added that Palmerston Primary had a school councillor on site two days a week and an anti-sexual harassment officer. The spokesman said behaviour management policies at the school were in place and had been presented to the school's Parents and Citizens Association.

When asked whether parents taking children out of schools as a result of bullying was normal, a spokesman said "the directorate does not believe this experience is common in ACT schools. Parents choose to enrol their child in schools for a variety of reasons."

The spokeswoman for Ms Burch said parents were "right" to raise concerns and "bullying in schools is unacceptable and the ACT government continues to take action to ensure that our schools are safe and welcoming places for all children."