Vic schools get more threat calls

Victoria schools are responding to threatening phone calls for the third time in a week.

Police said several schools received calls on Wednesday, a day after 17 schools across the state were evacuated and or placed in lock down following similar threats.

"Police are aware of the threats which we believe are hoax calls similar to the ones received yesterday," a Victoria Police spokesman told AAP on Wednesday.

"We believe the aim is to cause disruption and attract media attention," the spokesman said.

St Joseph's Primary School principal Michael Gray confirmed his school was one of many to receive a call on Wednesday just before 10am.

He said 590 students were evacuated from the school but returned to class after about an hour.

The type of threat made on Wednesday has not been disclosed, but last Friday an automated message warned schools a bomb was on their premises and on Tuesday the threats were either about a bomb or that shooting would occur.

Education minister James Merlino says police are investigating whether some of the calls received in Victoria on Tuesday originated from Nossal High School and whether its telecommunications systems had been hacked.

"It's certainly a line of inquiry for Victoria Police," he told ABC 774 on Wednesday.

Nossal principal Roger Page said the select entry school, in Berwick, was co-operating with police.

Premier Daniel Andrews described the calls as a "shameful act".

"This is not only an inconvenience, its deeply frightening and very distressing for many students," he told reporters on Wednesday.

Victoria Police chief commissioner Graham Ashton said because the calls are automated it's difficult to determine whether an individual or group was behind them.

Schools in Tasmania, Queensland, NSW, ACT, and elsewhere across the country have received similar hoax calls since Friday.

Tasmania Police have said the threats there on Tuesday appeared to have come from overseas and there was no credible evidence they could be carried out.