Education lobby groups say that a plan by Brindabella Christian College to establish a new ''campus'' at Charnwood High School would pose a direct danger to established schools in the surrounding area.

Canberra's Parents and Citizens Council and the lobby group Save Our Schools have joined the protest against BCC's planned expansion into Charnwood, after public school teachers' union Australian Education Union, savaged the scheme in a submission to the ACT government.

The three groups are also worried about applications from Seventh Day Adventist outfit Canberra Christian College to build a school in the new Molonglo suburb of Wright and the At Taqwa Islamic School's plan for a new school in Belconnen.

The union, the P&C and Save Our Schools all say that the applications for Belconnen, if approved, could lead to school closures in the surrounding areas if the ACT government continued to use low enrolments as a reason to shut schools down, as it had in the past.

Save Our Schools' convenor Trevor Cobbold, a veteran campaigner for public education wrote in his submission that the proposed new schools would be direct threats to several schools in Belconnen. ''The establishment of a new primary school campus is also likely to impact on other schools in the region and could affect their viability if the ACT government continues to use excess capacity and low enrolments as reasons to close schools,'' Mr Cobbold wrote.

''According to Brindabella College's application, students are likely to come from suburbs in the north-west Belconnen region (and elsewhere), and so draw enrolments from existing schools.''

Mr Cobbold wrote that Belconnen schools were nowhere near capacity and parents who chose a Christian education for their children already had plenty of choices in the area.

''There are nearly 2000 excess places in the north-west Belconnen area and average capacity utilisation is only 69 per cent,'' he wrote.

''There are 899 excess places in government primary schools and average capacity utilisation is 78 per cent.

''There are already seven private schools in Belconnen that offer a Christian education for primary school students, including three in the north-west Belconnen region.''

ACT P&C Council president Vivienne Pearce called on Education Minister Chris Bourke to consider the legislative requirements when assessing applications for new schools.

''The act requires the minister to consider both the impact on the ongoing viability of existing schools in the area and the community demand for the proposed schools,'' Ms Pearce wrote. ''Council has concerns over whether the proposed schools meet the requirements set out in this section.''

But Christian Schools Australia chief executive officer Stephen O'Doherty said the public education advocates were making misleading claims about Brindabella's plan.

''These other groups need to stop making misleading claims about these applications. What they're saying is based on untrue numbers,'' Mr O'Doherty said.

''Brindabella Christian College is very committed to providing choice for parents in north-west Belconnen.

''This is not about saying that one school is better than another, [BCC] has no beef with public education and it is disappointed that the public education advocates are so vocal in opposing the proposal.''

A spokesman for Dr Bourke said the proposals would be judged on whether they met the legislative conditions for new schools.

''Under the Education Act 2004, the minister's decision whether to grant in-principle approval for a proposed new non-government school or campus is based only on two criteria,'' the spokesman said.

''These are the impact of the proposal on existing schools; and whether there is demand in the community for the proposal.''