"The population for Rotorua is growing, and the teaching population workforce is ageing [and retiring], so there is a greater demand for teachers. There hasn't been thought gone into how to replace these teachers."
Teachers' salaries have been completely eroded over time compared to other professions, and what they can earn overseas
A report from the New Zealand Post-Primary Teachers' Association (PPTA) recently confirmed Auckland teachers were moving out to the regions because the city was getting too expensive.
On Thursday, the Education Gazette - a Ministry of Education website dedicated to teachers - said there were 14 teaching job vacancies in Rotorua. None were for physical education teachers.
Teachers for subjects such as English, technology, science and mathematics were being sought, but Mr Walsh said there were not enough teachers to fill the roles.
He thought this was because the pay in the private sector was higher, therefore attracting more young people.
More money was needed for incentives to increase job satisfaction, he said. This would be through increasing salaries and having fully-funded scholarships to branch into other subjects.
"Principals and boards should be given money to be able to recruit and retain teachers in hard-to-staff areas," he said.
"Teachers' salaries have been completely eroded over time compared to other professions, and what they can earn overseas."
A decrease in workload was also vital. Assessments required for qualifications such as NCEA meant teachers were working under extreme workloads and suffering burn out.
Mr Walsh said there was also a lack of relief teachers.
"People who want to teach are still teaching, and people who retire don't want to go back to teaching relief. Young people want to make more of a career [with full time teaching], and because of the nature of the job, it's hard to get to know the kids you're teaching."
New Zealand Secondary Principals' Council chairman James Morris said it was "not surprising" Rotorua was also struggling with a shortage, and agreed about the lack of relievers.
"There's been a 30 per cent drop [of secondary graduates coming from the teachers' college] in the past three years," he said. "In the years before that, there've been a lot of PE graduates but not many in the other areas."
As for relievers, he said there were more factors than just the ageing workforce.
"Because there's a shortage, teachers wanting to work fewer hours have been convinced to work a lot more. We dragged a lot of people who were relievers and got them on a more permanent basis."
The Education Council also changed the rules regarding registration in 2015, and increased the fees.
"It became very expensive to do the registration course," said Mr Morris. "We lost a lot of teachers like that."
One way New Zealand could boost the teaching profession would be with scholarships and school-supported programmes for student teachers.
But as Mr Walsh said, that would require more funding.
"Most schools will have trainee teachers in, but tend not to get any recompense for that. Teachers do it as part of what they see is their professional responsibility".