Students are turning up to class ravaged by ice, or crystal methamphetamine, with some teachers now working in pairs for safety.

At the same time, parents are calling for teachers to receive special training to help them respond to students using the drug. 

Principals who spoke to Fairfax Media – but did not want to be named because they were concerned about their school's reputation being damaged – recounted the following incidents;

Victoria's Youth Drug and Alcohol Advice acting manager Cara Munro Steensma said the service had received calls from schools that were worried about ice use among students.

"The calls tend to be from schools where there is a high number of students who experience disadvantage," she said.

Ms Steensma said many of these students also experienced mental health issues, family breakdowns, unstable housing, poverty and had involvement with child protection. Most were 17 or 18-years-old, she said.

Jackson Oppy, the general manager of one of Melbourne's largest rehabilitation clinic, Raymond Hader, said schools were "totally overwhelmed".

They are witnessing behaviour they have never seen before, he said.

"Kids are psychotic, aggressive. They are turning up to schools with no sleep for days and sitting in classes with glazed eyes staring forward," he said.

He has also heard of mothers selling the drug outside schools.

Mr Oppy – a recovered ice addict – said schools found the drug very difficult to deal with, so they ignored it.

One parent, who did not want to be named, said her son would arrive at school on Monday after using ice on the weekend, and fall asleep at his desk.

After he became addicted to the drug, his grades plummeted.

"His academic performance fell off a cliff. The drug has a devastating impact on your ability to concentrate and your attendance," she said.

She said many parents were reluctant to raise concerns with schools about their child's drug use because they were afraid they would be expelled.

They are also concerned schools will report the matter to police and their child will end up in the justice system, instead of receiving help. 

Schools struggled to balance their competing obligation; to the student as an individual and also their need to protect the wider school community, she said. 

"There's an inherent conflict and that means the welfare of the student is too often subjugated and that is wrong." 

She called for better training for teachers so they could identify and appropriately respond to students using drugs. 

Crime Statistics Agency data released last year revealed that drug trafficking arrests involving Victorian state and private schools have almost doubled over the past five years.

 However, no official figures are available on the number of students in Victorian schools using ice.

Australian Principals Federation president Julie Podbury said she was aware of a situation where ice-affected parents showed up at a remote, rural school and frightened teachers.

"They were concerned about their wellbeing and safety and their students'," she said. She said principals were reluctant to speak openly about drug issues because they were worried it would damage their school's standing in the community. 

New laws introduced by the Andrews government have made it a special criminal offence to sell ice near schools.

An education department spokesman said that schools play an important role in educating young people about the dangers of drugs.

"They also provide counselling and other forms of emotional support and where necessary will work with other agencies like Department of Health and Human Services or community groups to help students and their families tackle drug use," he said.

The government has developed an online training package to help frontline workers, including teachers, respond to those affected by ice.