Threat callers are cowards: Vic minister

The anonymous callers who are making threats to Victorian and interstate schools are cowards who will be punished when caught, Victoria's education minister says.

James Merlino told reporters on Tuesday these "anonymous cowards" would face "the full force of the law" for calls that caused almost 20 schools in Melbourne and the state's east to go into lock down or evacuate on Tuesday.

Victoria Police chief commissioner Graham Ashton said each threatening phone call had to be treated seriously but all so far appeared to be hoaxes.

It follows similar threats made on Tuesday to schools in Tasmania, Queensland, NSW and the ACT, and across the country since Friday.

Tasmania Police say the threats appear to come from overseas and there is no credible evidence they could be carried out.

Mr Ashton said the E-Crime division was co-ordinating the Victorian investigation into the calls, which are not being considered terrorism-related.