The Victorian teen, a 17-year-old from Mildura in the state's north, is accused of sending threats to schools in three states via secret email accounts between May 2016 and April 2017, a children's court heard on Thursday.

Police allege the boy, who cannot be identified for legal reasons, at times sent the hoaxes so students could get out of exams or have days off, the Sunraysia Daily reported.

Investigators claimed on one occasion the boy had a conversation with another student online asking: "Do you want a couple of days off". Police also alleged there were texts sent between the accused and a student from a school requesting threats so they could get out of exams.

The teenager was arrested and charged on Thursday with 74 offences, including nine counts of making a bomb hoax in Victoria, 13 in NSW and 49 in South Australia.

The court heard the primary target was Coomealla High School in Dareton, about 20 minutes from Mildura, where the boy is alleged to have made 14 threats.

A school on the Mornington Peninsula was targeted one to three times, the court heard.

A police prosecutor told the court a similar modus operandi was used to make a series of bomb hoaxes last year.

The hoaxes, he said, would be sent to schools via "guerilla mail", a free disposable email address, often featuring the words "pipe bomb" and "allahu akbar".

Some of the emails would allegedly say there was a bomb in the school due to go off and students and staff were in danger.

The court heard the case against the teen - who was bailed - was largely circumstantial, whereby people requested the bomb threats from the accused and the threat ultimately occurred.

Police did not oppose bail for the boy, subject to him be prevented from using electronic devices except with direct?????? supervision of a parent or teacher.

The magistrate said had the accused not been a child, he would have likely been refused bail and be facing a significant prison sentence for the "extremely serious charges".

"You're a child and the bail rules are very different to that of the adult court," he said.

"You pull any other stunt like this . . . it's likely no bail will be granted on the next occasion."

He will go before court again in June.

It comes as another teenager, this time an 18-year-old from Israel, was charged by Israeli authorities with making 2000 automated bomb hoaxes to schools, airlines, hospitals and Jewish centres in the US, Britain, Australia, New Zealand and Israel.

Michael Ron David Kadar, who lives in the city of Ashkelon, is understood to have no connection to the Victorian teen.

But the Victorian E-Crime Squad did lead the Australian arm of the international investigation.

"The Victoria Police E-Crime Squad provided vital cyber evidence, which resulted in the arrest of the Israeli suspect," Superintendent Pat Boyle said.

"Israeli police acknowledged they could not have done it without us."

About 590 bomb hoaxes were made to schools in Queensland, Tasmania, NSW, the ACT, Victoria and South Australia over four consecutive days in February 2016.

In Victoria, the locations included Melbourne, Wangaratta, Bendigo, Latrobe Valley, Geelong, Mildura, Ballarat, Lakes Entrance, Phillip Island, Wodonga, Shepparton and Bairnsdale.

Many received the same automated message about a bomb on site.

It caused major chaos as thousands of children were evacuated, exams were disrupted and police resources were diverted.

At the time, an online account with the name Evacuation Squad claimed responsibility and was asking people to pay bitcoins to have their school of choice targeted.

Israeli authorities have not offered a motive for the attacks but Mr Kadar's lawyer in Israel said the teenager had a high IQ but the emotional intelligence of a five-year-old.

Mr Kadar, who is Jewish, allegedly used masking technology to hide his location and disguise his voice.

He allegedly set fees for particular calls and kept a log of all calls on a flash drive found in his laptop in his bedroom.

Israeli media reports say he had almost $US500,000 in his bitcoin account at the time of his arrest, some purportedly coming from students who wanted exams postponed.

- Sunraysia Daily, Reuters