An ACT Policing spokeswoman said officers attended the hospital in response to the call but she would not detail the nature of the threat.

"We can confirm that the hospital was searched and nothing suspicious has been identified," the spokeswoman said.

"Police are warning that it is an offence to make such threats and every effort will be made to identify those responsible. The offence carries heavy penalties."

Police would not say if the call involved threats of a bomb, after schools around Australia and overseas were targeted with pre-recorded threatening phone calls. Several Canberra schools also received new calls on Wednesday.

Earlier an ACT Health spokeswoman referred questions to police.

The police spokeswoman urged anyone with information to contact Crime Stoppers.

Five Canberra schools were evacuated on Tuesday after a series of a bomb threats, believed to be part of a concerted international school bomb hoax.

Over the past week, schools across Australia and overseas have received specific threats of harm. A series of Melbourne schools received threatening hoax calls to about bombs or planned shootings.

Serious threats have also been received at schools overseas and in Tasmania, Queensland and NSW in recent days.

The ACT Education Directorate wrote to parents on Tuesday afternoon to assure parents and carers that safety procedures had all been adhered to.

Contact Crime Stoppers on 1800 333 000 or at act.crimestoppers.com.au. Information can be provided anonymously.