The teachers were joined on Wednesday, March 27 by a massive campaign billboard and NSW Teachers Federation president Henry Rajendra, who said the state's public schools are currently underfunded by about 11 per cent, or $1.9 billion, for this year alone.

"That kind of money would have allowed our system to employ an additional 10 to 12,000 extra teachers," he said.

"The ramifications of an underfunded public school system has played itself out in this particular region, because of the underfunding teachers are overworked, they're stretched and regrettably many are leaving the profession all together.

"We started the school year this year in this region, according to Department of Education figures, with 103 unfilled vacancies, impacting 34 per cent of the 300 schools in this area and that is unacceptable."

Mr Rajendra said the Teachers Federation is calling on the prime minister and the federal government to close the funding shortfall.

In Paterson there are 18,754 students attending public school, which is 67.5 per cent of the electorate's total students.

The funding shortfall can be closed by improving the National School Reform Agreement, Mr Rajendra said.

"That agreement is between the federal and state governments about what they're going to lay out for the next four to five years in terms of funding. They're negotiating it now," he said.

"The current one expires at the end of this year. So we want them to do all the work now so that in the agreement we're at the 100 per cent."

According to the Teachers Federation, the funding shortfall is equal to more than 10,000 permanent school-based teachers.

"Students are impacted of course by the teacher shortages, schools aren't able to provide the full curriculum offerings that they would like to because they don't have the teachers to do so," Mr Rajendra said.

"The shortages result in uncovered classes, classes that are split, students under minimal supervision in the library or the playground.

"These are unacceptable conditions that impact on the learning of our students."

Inequities between public and private schools are also becoming starker with capital funding.

A report released by the Australian Education Union on February 24 highlighted the gap, with one Sydney private school, Cranbrook, spending more on a new pool and expanded fitness and drama facilities in 2021 ($63.5 million) than governments spent on 2549 public schools which educate over 472,000 students.

For NSW schools it also found: