The principal, Linda Heath, told the school community a perimeter fence would allow "increased inclusiveness and integration for our students with special needs to have access to playground equipment and the oval with safety".

And a number of parents have been told that once the perimeter fence is up, the internal fence for students with special needs students can be removed.

Currently, Farrer runs a multi-aged classroom for students with autism from behind two metre bars. The unit has up to half a dozen students, a demountable classroom, a shed and a grassed area with trees. The contained space measures about 20 metres in length and six metres in width.

A parent at the school, who works in the disability sector and who did not wish to be named, said that when she first saw the area she had been "horrified".

"I think it is unfathomable why you would want to keep children behind bars," she said.

But she said the idea that the entire school would be fenced in was not an appropriate solution for the students with special needs, nor the wider school community.

There was also growing unease among some parents around the aesthetics of the special needs unit given the national debate that has sprung up around the containment of students in the wake of the autism cage scandal.

Farrer Primary parent Stacey Rippon – who has been campaigning for greater community consultation around the proposed perimeter fence – questioned whether it was being "rushed through" because the cage inquiry had called into question the appropriateness of the internal gated area for students with autism.

"When you first see the intimidating height of the MAC unit fence, there is no way of avoiding asking yourself what possible reason could there be to justify that, but then you just get accustomed to it. Only now in light of the media attention on 'cages' for children with additional needs have parents been discussing how it has taken on a more sinister appearance."

ACT Director-General of Education Diane Joseph said there was simply no comparison to be drawn between the "inappropriate structure" at the centre of the autism cage investigations, and the set-up at Farrer, saying the playground was "fenced to ensure the safety of children".

She also stressed that mainstream students could use the space if they wanted to and that students with autism spent time in the mainstream classes.

She said all schools were able to consider the option of perimeter fencing – which was an increasingly popular way to manage school security.

Currently, 67 Canberra government schools overseen by the directorate have some level of fencing, while 10 schools had refused.

The idea of a perimeter fence was first raised at Farrer in 2012 by the then principal, but had been put on the backburner after the P&C rejected it outright.

But in March this year a newsletter was sent out to say the fence was going to be installed.

Some members of the school board and community have supported it on safety and security grounds, noting the school had been the target of break-ins and vandalism over the past 18 months.

But Ms Rippon said many in the school resented the lack of consultation being undertaken and believed that such an imposing fence all the way around the campus would be a negative image for students and would prevent community enjoyment of, and engagement with, the school.

Last week Ms Rippon wrote to Education Minister Joy Burch, Ms Joseph and the head of the government's review into managing children with extreme behaviours, Professor Tony Shaddock, to plead for the fence to properly debated.

She said that if the perimeter fence was being used to replace the fencing for the special needs unit then that decision needed to be made more openly with the school community and should be made only after the Shaddock review was completed.

"I suggest that the rationale that the proposed fence is for the MAC kids is misinformed and damaging, for specific students with disabilities, Farrer Primary School and any other school. I am proposing that the 'security fencing policy' be examined, taking into account any recommendations from Emeritus Professor Tony Shaddock's review, and that any decision or action related to perimeter fencing for Farrer Primary School be indefinitely deferred," Ms Rippon said.

The newly-announced Director for Families and Students, Tracy Stewart, said the directorate would examine all school spaces for children with disabilities in light of the findings of the Shaddock inquiry.

"We really look forward to getting some meaty recommendations about what we are doing well and what needs to change. I don't think the system can't be improved," she said.

Ms Joseph said: "It is possible that the space could be adjusted if a perimeter fence was installed, however the perimeter fence decision would need to be finalised before any concepts could be developed further."

She believed greater consultation measures were being put in place at Farrer to deal with parental concerns.