Sydney: Australian police were investigating “threats” on Monday against four hospitals in the city of Sydney amid reports of at least one being partially evacuated over a bomb threat, just days after the country raised its terror alert level to “high”.

Patients and hospital staff were evacuated from parts of Prince of Wales Private Hospital, while police also went to Royal Prince Alfred hospital, Longueville Private hospital and Royal North Shore hospital, media reported.

Police and health department officials were investigating threats made on Monday afternoon against a number of public and private hospitals in Sydney, a spokeswoman for police in the state of New South Wales said, but gave no details.

A spokeswoman for one of the hospitals said the incident was minor and staff were continuing with their duties.

Last Friday, Australia raised its terror threat level to “high” for the first time, citing the chance of terrorist attacks by Australian citizens radicalised in Iraq or Syria.

At the time, officials said they had no knowledge of a specific attack plan.

David Irvine, the outgoing head of the Australian Security Intelligence Organisation (ASIO), has said the number of Australians returning from fighting with Islamic State and other radical groups pose a growing risk.