Public schools across NSW will have their budgets slashed by up to $148 million and deputy and assistant principals will be forced back into the classroom to fill teaching shortages.

The 1.25 per cent budget cut for the rest of this calendar year has been described as a necessary reset by the state’s education minister.

As well, executive and deputy principals will have to spend up to three days a week in classrooms to fill staffing gaps.

The news was delivered by Education Minister Prue Car in a letter to public school principals on Tuesday afternoon.

Car said the budget reduction reflected declining public school student numbers and an over-staffed executive cohort.

Enrolments have dropped by nearly 25,000 in the past four years as more students shifted to private education.

Education Department secretary Murat Dizdar stressed the cuts would come from discretionary funds, noting the budget reduction could have been avoided if a deal had been struck with the federal government for more money.

NSW has been pushing for the Commonwealth’s share of public school funding to be lifted to 25 per cent, up from the current figure of 20 per cent of the required level.

States pay the remaining 80 per cent but NSW and most other jurisdictions are falling well short of meeting that target, leaving public schools short-changed by billions of dollars a year.

Dizdar doesn’t expect the budget cuts to be easy for schools, but the government had to make the “tough decision to right-size school budgets” after the end of COVID-era provisions.

“We’ve been dropping student enrolments since 2020 and we’re determined to win back those enrolments,” he told ABC Radio on Wednesday.

Dizdar added the public school system could not afford to be “too top heavy” with executive staff and it was crucial to ensure all classrooms were covered, with 1800 teacher vacancies to work through.

But Opposition Leader Mark Speakman said principals had been blindsided by the decision and the timing was concerning.

“This announcement came without warning and now school principals are forced to look at cutting staff and programs to find savings,” he said.

“The school year is well underway, meaning key decisions have already been made and people have already been employed for specific roles.

“This is not good enough and our kids deserve better.”

The NSWS government rejected suggestions the cuts were required to pay for recent teacher pay rises, saying no permanent staff would be lost.

The Parents and Citizens Federation of NSW said the cuts would burden parents, carers and volunteers.

– AAP