As New South Wales schools grapple with a chronic teacher shortage, resignations are for the first time outstripping retirements and principals are clocking up to 70 hours work a week, MPs have been told.

Teachers Federation president Angelo Gavrielatos on Wednesday told a parliamentary inquiry the shortage was worsening, with vacancy lists growing more than three fold in the past two years despite the government launching a $125 million recruitment drive.

There are more than 3300 teaching vacancies across the state.

“That often-cited, much-heralded (recruitment) strategy has delivered three people from overseas and five mid-career teachers – one of whom has already left,” Mr Gavrielatos said.

“It is a failure of delivery in education … our kids are missing out. Our teachers are burning out”.

More teachers are quitting than retiring and there’s an 83 per cent increase in insecure work (temporary contracts), according to official figures.

Mr Gavrielatos said regional and rural areas were particularly disadvantaged, with 55 per cent of all vacancies outside major cities.

The parliamentary inquiry, chaired by One Nation MP Mark Latham, is examining “the adequacy of the government’s response to teacher shortages and education outcomes”.

Mr Gavrielatos was speaking after the release of a study on Wednesday that found the problem was “acute”.

“NSW Teachers’ pay has gone from bad to worse, with the situation set to deteriorate further,” according to the University of Sydney Business School report.

While salaries had declined dramatically between 2000 and 2020, especially compared to equivalent professions, the situation had over the past two years declined particularly due to inflation which had escalated rapidly since 2021.

The challenge had been “decades in the making”, it said, with skills associated with new technology rising but so too workloads.

“It will be hard to change current arrangements quickly.”

With federal Treasury forecasting inflation will exceed five per cent in 2022/23 and 3.5 per cent in 2023/24, the report found a wage increase of 15.5 – 25.5 per cent “can readily be justified”.

NSW Secondary Principals’ Council president Craig Petersen said shortages were adversely impacting educational outcomes.

“A single vacancy in a secondary school means up to six classes may not be covered by an appropriately qualified teacher – that’s potentially 190 students whose learning is likely to be impacted every day,” he told the inquiry.

“There can be a real difference between statistics and figures on a page and people in front of classes,” Mr Petersen said.

“It’s not enough just having any teacher in front of the class. Students need to have their teacher in front of them every day and their teacher needs to be a teacher of that subject”.

He noted the unsustainable workloads and salary disparities with other professions were contributing to an overwhelming sense of being undervalued professionally.

Mr Petersen said a survey his group had conducted showed high school principals were working an average of 65 to 70 hours per week.

A separate parliamentary inquiry that handed down its report in November said “failure to act decisively now, at a point where we are clearly experiencing acute teacher shortages across the state, will harm both current and future generations and their academic outcomes”.

The government is due to respond to the report on 8 February.