The government’s education funding plans after 2018 may force private schools to raise fees and is cut in real terms, Independent Schools Queensland says.

Private schools could be forced to increase their fees if the federal government doesn’t change its plans for education funding.

But the sector has been somewhat mollified by Education Minister Christopher Pyne’s promise the commonwealth will keep its direct relationship with private schools and not channel funds through the states.

The federal budget showed school funding will rise from 2018 in line with the consumer price index.

That’s predicted to run to about 2.5 per cent, or about half the rate of increase the previous Labor government promised schools.

Independent Schools Queensland says this is a cut to government funding in real terms.

“This could lead only to a reduction in programs and education quality or, in the case of independent schools, significant increases in fees,” executive director David Robertson wrote in The Australian on Wednesday.

Using CPI doesn’t reflect special increased costs the schools face, such as implementing the national curriculum or the movement in salaries, he said.

It’s not unreasonable of schools to expect government funding to increase in line with a specific education-based measure.

Meanwhile, Mr Pyne has told a Christian schools forum he wants to maintain the direct funding relationship the commonwealth has had with private schools since the 1960s.

The commission of audit suggested the federal government withdraw from funding schools entirely and instead give the money to the states and territories to hand out.

“I am not attracted to that model,” Mr Pyne told the forum in Canberra.

The second High Court challenge to the school chaplaincy program, now being considered, could affect the direct relationship with private schools, but Mr Pyne said the government would deal with that if it in fact happened.