The NSW Teachers Federation has launched a campaign - including television, digital and print ads - to address growing teacher shortages and highlight the growing challenges they face as they lobby for a pay rise.

A survey of more than 4000 public school teachers who are union members found more than half - 58 per cent - are reconsidering their career choice due to the workload.

"As we have seen so clearly demonstrated in the past 18 months, teachers in public schools are committed professionals determined to do whatever they can to ensure every child gets a high quality education. But there aren't enough of them right now," NSWTF president Angelo Gavrielatos said on Thursday.

"We are in a crisis situation with worsening teacher shortages at a time when schools are preparing to reopen and we need every child to be fully supported in the classroom."

An overwhelming 95 per cent of survey respondents said teacher shortages were a significant issue, and four in five teachers in secondary or combined schools said they had been forced to teach outside their area of subject expertise as a result.

More than half said there are vacant permanent or temporary positions at their school, and 93 per cent said their school had trouble attracting casual teachers.

"At the same time as university enrolments in teaching courses are plummeting, public school enrolments are starting to soar and research shows between 11,000 and 14,000 more teachers are going to be needed in the next decade," Mr Gavrielatos said.

The results show it's impossible to address shortages without first addressing pay and work conditions, he argues.

An independent inquiry into the work of teachers, headed by former WA Premier Geoff Gallop, in February warned the same thing.

The Teachers Federation is lobbying for a five-to-seven per cent pay rise each year, which it says will begin to reverse the decline in teachers' wages compared to other professions.

They're also seeking an two additional paid work hours each week for teachers to prepare for classes, after the Gallop inquiry found the preparation time afforded teachers had not changed since the 1980s.

Australian Associated Press