A new study released by Teachers Health Fund has found the main cause of stress for school principals was the "sheer quantity of administrative work" they are required to perform, and the lack of time to focus on teaching and learning.
The AEU says schools need to be properly resourced to relieve the rising principal stress level shown in the Australian Principal Occupational Health, Safety and Wellbeing Survey.
AEU Federal president Correna Haythorpe says school systems needed to do more to support principals and ensure all schools had the resources they needed for their students.
"This report paints a concerning picture of growing demands on principals, and rising levels of personal stress," Ms Haythorpe said.
"Being a principal will always be a difficult and challenging job, but we can reduce some of this stress by making sure all schools have the resources they need."
The AEU's 2016 State of Our Schools Survey found that 45% of principals believe their school is under-resourced or significantly under-resourced, and 48% said they struggle to fill staff vacancies.
"Lifting resources will deliver better results for students, as well as reduce stress on educators," says Ms Haythorpe.
"This is why we need the Turnbull Government to deliver the full six years of Gonski funding, rather than push ahead with its plan to stop $3.8 billion in extra resources going to schools."
The survey findings back up data from the Teaching and Learning International Survey (TALIS) from 2013, which found that 80% of principals reported that inadequate resources impact on their effectiveness as a principal, while 79.8% said that high workloads impacted on their effectiveness.
"Calls for greater autonomy for schools often ignore the fact that this puts increased responsibility and stress onto principals, unless they are also given more resources," Ms Haythorpe said.
"The research also confirms that principals are being exposed to increasing levels of violent and bullying behaviour, and that this contributes to the stress of the job.
"As well as supporting principals exposed to violent behaviour, we need to make sure that schools have the resources for students to get the individual support and programs they need to reduce difficult behaviours."
Ms Haythorpe said it was deeply concerning that less than 10% of principals saw their primary support as coming from their employers or education departments.
"If we want teachers to put up their hands to become the next generation of principals, we need to make sure that principals are being supported."