Thousands of parents in Bennelong will receive letters from the Catholic education authority on Monday warning of a $1.1 billion funding shortfalI as the crucial byelection campaign enters its final week.

Ahead of Saturday’s byelection, Catholic Schools NSW asked Bennelong candidates about three key education issues, including how their party would “address the $1.1 billion recurrent funding shortfalI to Catholic schools”.

The letter – which will go home with the 3298 students enrolled at the electorate’s 11 Catholic schools – is an uncomfortable development for Liberal John Alexander, who was forced in his response to defend a government policy the Catholic sector has said unfairly targeted its schools.

In his response to Catholic Schools NSW boss Dallas McInerney, Mr Alexander said the government’s reforms meant “all non-government systems will be treated equally for the first time ever”.

“And as Catholic systems can redistribute Commonwealth funds, as is now clearly provided for by the new legislation, there is no reason for schools or sectors to need to increase fees or reduce funding levels to schools which need it most,” he wrote in his response.

Last month, Mr McInerney wrote to the candidates, accusing the Turnbull government of imposing a “$1.1 billion transition penalty” on Catholic school systems “as a result of its new schools funding policy”.

“In Bennelong, all 11 Catholic systemic schools will be denied the 10-year transition afforded to independent stand-alone schools,” he wrote.

“Catholic schools in Bennelong will be $9.8 million worse off in 2018 and $52.3 million worse off over the decade to 2027.”

Labor candidate Kristina Keneally used the letter to attack the government over what Labor has claimed is a $17 billion cut to schools nationally, including “significant funding that has been unfairly ripped from parish Catholic schools”.

“We understand the pressure Catholic schools are under due to the Turnbull Government’s cuts,” she wrote.

“That is why Labor is committed to full and fair funding for low fee Catholic schools.”

Catholic schools have slammed the funding shakeup as unfair and claimed it will lead to fee increases, but the government says the sector had been overfunded under the existing regime.

Catholic Schools New South Wales spokesman Jim Hanna said: “This exercise was carried out so our parents, teachers, professionals and all supporters of Catholic education in the Bennelong electorate can make an informed decision on Saturday 16 December.”

Mr Alexander holds the seat by nearly 10 per cent but recent polls have suggested the result will be much closer.