The NSW Teachers Federation says all Hunter public schools are underfunded and is calling on Prime Minister Anthony Albanese to make up a $1.9 billion annual shortfall across the state.
The federation staged a protest outside Hunter School of Performing Arts at Broadmeadow on Tuesday as part of a pre-election campaign in federal seats across NSW.
Federation president Henry Rajendra said the Albanese government had a moral obligation to make up a $1.9 billion shortfall in NSW school funding this year under the National School Reform Agreement (NSRA) between the federal and state governments.
"Whilst private schools are funded at the minimum level of funding or indeed many are funded above that minimum level of funding, our public schools are 11 per cent below that benchmark," he said.
"That means our schools are going without the resources and staffing that our kids need to meet their needs."
Mr Rajendra said the missing money could employ an extra 10,000 permanent teachers in NSW to help reduce class sizes and workloads.
"There's no greater urgency than to get our public schools up to the minimal level of funding that they've been denied for decades.
"With the shortfall in funding, because our teachers are burnt out, many are leaving the profession or taking extensive leave.
"In this particular [Northern] region, according to department figures, we started the school year with 103 unfilled vacancies.
"That's impacting 34 per cent of the 300 schools throughout this region. That is unacceptable."
Ninety-eight per cent of public schools are underfunded in relation to the baseline schooling resource standard agreed to by state and federal governments under Gonski reforms introduced more than 10 years ago.
An expert panel conducted an independent review of the NSRA last year, finding that all schools should have access to 100 per cent of schooling resource standard funding "as soon as possible".
The review will help inform negotiations between state and federal education ministers on new funding levels to be announced next year.
"A country that under-funds public schools but over-funds private schools, I think there's something wrong there," Mr Rajendra said.
He said some well funded private schools in Sydney were "splurging on unnecessary vanity projects such as equestrian centres and Scottish castles".
The NSW government signed off last year on 4.5 per cent pay rises for teachers, increasing starting salaries from $75,791 to $85,000, but Mr Rajendra said the federal government now needed to come to the party with more education funding for the states.
Hunter School of Performing Arts teacher and union representative Natalie Hudson said staff workloads had increased alarmingly since she started her career in 2006.
"Workload has exploded for teachers in terms of the tasks we're required to do," she said.
"Not one public school in NSW is fully funded, and the Prime Minister has the time now to do something about it."
