Almost half of ACT families earning $156,000 a year or more sent their children to public schools last year. The figure was a 5.1 per cent increase on that of 2006, where 44 per cent of high-income families chose the government school sector.

The number of independent school enrolments declined almost in parallel, according to the data from the Australian Bureau of Statistics. About a quarter of wealthy families chose independent schools in 2006, compared to 20.1 per cent in 2016.

Catholic school enrolments remained steady over the decade. Even with the move towards public education, slightly more high-income families chose the non-government sector last year, with 50.9 per cent enrolling their children in independent or Catholic schools.

Association of Independent Schools of the ACT executive director Andrew Wrigley said the data was an "absolute living example of people making the choice for the best fit for their child".

He pointed to enrolment pressures in both sectors as contributing to the figures and said many non-government schools still boasted healthy waiting lists.

"The ACT is getting to be a tight market," he said.

"There's enrolment pressures in government schools, there's enrolment pressures in independent schools. We just don't have the seats for everybody."

More than 60 per cent of all ACT students were enrolled in a government school in February this year with the remaining split almost evenly between the Catholic and independent systems.

The Education Directorate has hired the Australian National University to help improve its modelling for school capacity as several schools in north Canberra, Telopea Park School in Barton and North Ainslie Primary grapple with enrolment pressures.

ACT Parents and Citizens Association president John Haydon said the 5 per cent increase in public school enrolments among wealthy families "doesn't sound like a massive shift to me" but described it as "a good thing".

He noted that public schools enrolled students of all backgrounds. Figures from this year show almost 70 per cent of special needs enrolments and about 80 per cent of Aboriginal and Torres Strait Islander students were enrolled in government schools.

Public education lobby group Save Our Schools has written almost 80 per cent of Canberra's low socioeconomic students were in government schools last year.

"The big difference between private schooling and public schooling is that the public schools take everyone, whatever disabilities the child may have, whatever disabilities they may suffer from a family background point of view - violence at home, those sorts of issues," Mr Haydon said.

"That just means the resource demands on the public schools are much greater than they are in the private schools.

"If more children from well-off families are going to public schooling, well that's terrific, because it just adds to the diversity and it helps to redress that balance [in funding]."

- with Eryk Bagshaw.