Teachers are "losing the joy of the classroom", spending more time on administration and less time with students, according to the state's peak body for educators' rights.
Heading back to term three this week, public school teachers are feeling "increased stress" beyond their regular job loads, said Riverina organiser of the NSW Teachers Federation John Pratt.
"We relaxed at the end of the last term thinking things had gotten better or were becoming better," he said.
Following the resurgence of COVID-19 cases across the border in Victoria, Mr Pratt said the feeling of trepidation had returned to the classroom.
"The mood has changed, we're a little sombre and wary of going back for term three," he said.
"Especially since our HSC students are heading into their trials - some even this week - teachers are pulling out all the stops, as they always do, to help their students."
A survey, conducted in 2018, entitled Understanding work in schools: The foundation for teaching and learning collated the experience of up to 18,234 public school teachers across the state.
Up to 87 per cent of the respondents said they believed workloads had increased significantly in the five years to 2018 and would be working more than 50 hours each week.
Meanwhile, between 91 and 97 per cent of respondents said the increased work they are doing each week was almost entirely administrative.
Mr Pratt told The Daily Advertiser it is the increase to workloads and the stagnation of remuneration for overtime hours leading many teachers to "lose the spark".
"More and more I hear from teachers who have been in it for a long time is that the job is very different to what they signed up for and very different to what it once was," Mr Pratt said.
"The fun has been removed from their jobs because now it's a lot of data production and that joy of teaching is decreasing due to the [administrative] expectations."
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Mr Pratt explained that much of the school day is now spent "teaching to tests", with teachers expected to examine the learning outcomes of a topic every five weeks.
"Every five weeks, teachers are reporting on specific aspects of literacy and numeracy learning, they're spending so much time on testing leaving them little time for teaching students," he said.
"Think of a five-week period, it doesn't provide a huge amount of time to instruct 30 students. Five weeks is not a huge turnaround for the measurement of progress, it's unrealistic and it's stressful."
The Teachers Federation survey was completed two years ago, well before COVID-19 propelled teachers to the frontlines of increased stresses. But Mr Pratt believes the situation was already on its way to worsening.
"The survey showed up the frustrations teachers have in how much of their time is tied up with government strategies and not with producing great lessons, researching and the kind of academics they choose to do," Mr Pratt said.
"They end up doing that as extra on top of everything else."
Up to 86 per cent of respondents in the survey further said that the increased administrative work takes them away from their family commitments and makes achieving a work-life balance nigh on impossible.
Kooringal High School teacher and spokesperson for the Teachers Federation Michelle McKelvie said that experience was fairly common among her colleagues.
"It often will take over home life. The work doesn't finish at 3.30, it's not over just because you might walk out the door," she said.
"That has only gotten worse with [coronavirus]. Within 24 hours, teachers had to change and adapt to a completely new way of teaching, and that took time to learn. Their own time mostly."
To rectify the problem, Ms McKelvie said she would like to see public schools across the state be given greater access to resources and support.
"It's very hard to put a dollar figure on everything that teachers do," she said.
"Funding for extra support staff would help, smaller class sizes would mean there could be more one-on-one teaching, more resources are a good place to start."
The Daily Advertiser put questions to the NSW Department of Education on whether extra resources would be deployed to help teachers manage their duties and out of the classroom.
A response was not provided by the time of publication.