Canadian teachers and school principals say they're seeing a rise of "parent rage" -- increasing incidents of verbal abuse that are now sometimes turning violent.

In the past few years schools have been working hard to eliminate student bullying, and it now appears they have to add parent bullying to the list.

Veteran school principal Helen Evans, of the Toronto School Administrators' Association, says she's seen it all in her 28 years in education. But more of them lately -- and some recent incidents are especially worrisome.

"I know one principal just recently who was thrown across his office room by an outraged parent," Evans says.

Parents have been turning up at schools ready to blame teachers for their kids' poor grades or behaviour problems.

The growing number of abusive incidents has teachers so concerned that their union, Ontario Secondary School Teachers' Federation, plans to conduct the first major survey of all provincial schools. It comes at the request of members.

"They were telling us that there are times when they feel threatened, or intimidated or bullied or pressured in some way," says union president Rhonda Kimberley-Young. "What were trying to do determine is to what extent is that true and where is that pressure coming from."

In a recent national poll of school violence, the Canadian Teachers Federation found:

• 59 per cent of principals across the country had witnessed at least one parent verbally abuse a teacher
• 23 per cent had seen a parent physically assault or intimidate a teacher.

"We're talking about 160 to 170,000 possible incidents in a year," Canadian Teachers' Federation president Terry Price said.

"People are more stressed, they're overworked, they're overwrought, they feel they need to have the answers," says Evans. "They feel they need to steer us into answers that are right for their child, and with that we are finding an increase in the amount of rage."