As part of a new trial being run by the Education Department, professional mediators will help Victorian principals resolve complaints that are "complex, serious and involv(e) conflict".

Vexatious and difficult parents make life incredibly tricky for principals and can lead to tragic consequences.

In December, respected Victorian principal, Dr Mark Thompson, took his own life.

His son said inadequate support from the department in dealing with a parent's complaint led to his father's death.

Australian Principals Federation Victorian branch president Julie Podbury said some parents were "completely unreasonable with their demands".

They have become more protective of their children and many have unrealistic expectations of schools, she said.

"Some parents demanded that their child receive a certain grade," Ms Podbury said. "They expect their child to be enrolled at a school even if it is full, and their child to be moved to another class even if it is full. It's about the parent's rights and sometimes they don't give any consideration to the other side of the argument."

Anonymous abuse has also been hurled at some principals from parents who have set up fake email accounts, she said.

Since the start of September, Ms Podbury has received 54 calls for help from principals, the majority of whom are dealing with unreasonable complaints from parents.

"It produces very difficult and anxious times for school leaders. I am witnessing a deterioration in the mental health of principals."

Her comments are backed by preliminary figures from the Australian Principal Health and Wellbeing Survey, which paint a grim picture of the mental health of those in charge of the country's schools.

The survey shows that one in 10 principals thinks about self-harm or has a low quality of life.

The survey's author, Australian Catholic University associate professor of educational leadership, Philip Riley, said demands from parents fuelled the problem.

An Education Department spokesman said the mediators would "assist communication, promote understanding and help parties to create and agree upon outcomes that meet their needs and address their concerns".

The mediators will not offer legal advice or make or impose decisions on the parties, the spokesman said.

"While the majority of parent complaints are resolved at the school level, some complaints are complex and involve conflict and dispute," he said.

The mediators will be provided by Converge Australia and schools can choose to take part in the trial. Parents must also be willing to participate in the confidential mediation.

Parents Victoria executive officer Gail McHardy said mediation could be a useful tool for resolving complaints. She said parents often questioned the independence of a school's investigation into complaints.

"Complaints and dispute resolution is not an easy task and it's important to have those with the appropriate skills to manage it from beginning to end."

The state government is providing an additional 150 staff to support and advice principals.

It is also looking at establishing a Schools Commissioner; an independent umpire that would deal with complaints from parents and students.