Not all independent ACT schools have published their fees for 2017, but a sample of those that have shows average increases of 4 per cent rise in charges for Year 12. Inflation was 1.3 per cent and Australian wages rose by an average 1.9 per cent in the year to September.

The priciest place to finish school continues to be Canberra Grammar School, which will charge $22,700 per Year 12 student in 2017, an increase of 3.4 per cent.

Canberra Girls Grammar is not far behind at $21,600, a rise of 3.8 per cent on last year's tuition fees.

Tuition fees nudged a fraction higher at Radford College, board chairman Ian Morison said.

"Radford's Year 12 fees will be $16,045 per student in 2017 and across the whole college fees will increase by an average of 3.65 per cent," he said.

The totals reflected in the table include the $1400 per child contribution the school requests from parents for the building and maintenance fund.

Brindabella Christian College principal Bruce Handley said the school would stick with 2016 fee rates this year.

And St Edmund's College, the ACT's fifth priciest school, will roll out an increase of 2.2 per cent across the year levels.

The school's principal, Daniel Lawler, said the college was aware of financial pressures on families and knew their community covered a broad socio-economic spectrum.

"Our aim is always to be accessible to families whatever their circumstances," Mr Lawler said. "Thus we have kept our fee increase for 2017 to an absolute minimum by reducing costs and increasing efficiencies."

Trinity Christian School is believed to be one of few Australian schools that means-tests fees.

Families with combined incomes of less than $109,350 are encouraged to apply for concessions. The income threshold was elevated from a $107,206 in 2016. Overall, the school's Year 12 fees rose by 4 per cent for 2017.

Grattan Institute school education program director Pete Goss said wage growth in the education sector had softened but fee hikes also reflected market pressures.

"The general costs of education and training wages are much lower than they have been in the past," he said.

"Wage growth typically tracks CPI plus 1 per cent. As inflation has dropped over the last few years, wage growth in education and training across the nation has dropped from what it used to be of 3.5 to 4 per cent to now around 2.5 per cent."

He said the variable fee increases seen this year reflected the dynamics of the ACT private education market.

"As within any marketplace where there is a limited amount of supply, because schools cannot easily ramp up the number of students they cater to, and high demand, then prices can increase very quickly," Mr Goss said.

However, Association of Independent Schools ACT executive director Andrew Wrigley said it was "too limiting to just talk about wages" as schools had to withstand budget pressures such as expanding IT infrastructure, supporting staff in ongoing professional learning and, in some cases, capital works.

Compounding to these constant issues, he said schools were in a "horrible position at the moment where they are uncertain as to the funding model post 2017".

"Schools don't like to operate like that," he said. "They need certainty which provides a capacity for planning and communication with their communities."

He said private school boards struggled with having to increase fees but were unable to defray costs across a system and had to demonstrate financial viability to government to be registered.

"Schools have to consider their business case over many years," he said.

"The parents who choose those schools for their kids are expecting the schools to deliver. The governing bodies of those schools do everything they can to ensure the school is placed to deliver, has teachers of excellence and that teachers continue their professional learning so their pedagogy is up to date."

Correction: A previous version of this story incorrectly said St Francis Xavier College would lift costs by 8.1 per cent for final year leavers, it is actually 3 per cent.