A Melbourne neurosurgeon who was almost fatally stabbed on the job three years ago has slammed a lack of safety improvements for doctors, as another surgeon fights for life after a "one-punch" assault.

Dr Patrick Pritzwald-Stegmann, who is aged in his 40s, was punched in the head in the foyer of the Box Hill Hospital on Tuesday.

Joseph Esmaili, 22, from Mill Park in Melbourne's north, has faced the Melbourne Magistrates' Court charged with intentionally causing serious injury. He did not apply for bail.

Police allege Esmaili knocked Dr Pritzwald-Stegmann unconscious, before fleeing the scene.

Neurosurgeon Dr Michael Wong was almost killed when he was stabbed while working at Western General Hospital in Footscray in 2014.

Like Dr Pritzwald-Stegmann, he was attacked in the foyer. He had arrived for work and was confronted by a mentally ill man who had delusions Dr Wong had botched his recent surgery.

Last year, he raised concerns about the lack of security and protection for staff at hospitals, and has again questioned why it has not been improved.

Dr Michael Wong was stabbed as he arrived for work in 2014. ( Supplied )

"What is most tragic, and what really cuts deep in me is this attack at Box Hill Hospital happened in almost identical circumstances to what happened to me three years ago," he said.

"It begs the question: What has been done to protect hospital staff three years on?

"The hospital staff are precious resources.

"Yet this sort of attack highlights that the hospital environment is not a safe environment, and more security measures need to be in place."

Dr Wong said he was not calling for "airport security", but basic measures like security guards in public areas, separate entrances for hospital staff and areas that required security passes.

"I don't know what needs to happen before politicians or administrators wake up to the reality of increased violence in our hospital system," he said.

"How many doctors and nurses need to be hurt, traumatised, be disabled, even be killed, before something concrete can be done?"

Dr Wong said his thoughts and prayers were with Dr Pritzwald-Stegmann and his family.

Government will make security improvements 'a priority'

The Victorian Government said it was deeply concerned by the attack and it would talk to health groups to design new safety measures at hospitals.

"The sad fact is that this seems to have been in the general visitor, front door area that raises a whole new set of issues," Acting Health Minister Martin Foley said.

"We will meet other health professionals and we'll make sure places like hospitals are secure and safe for everybody that comes into them.

"We'll come together with a plan as to what needs to be done and then we will take that plan through the normal processes and implement it as a priority."

Victoria Police said the victim was leaving the Box Hill Hospital when he got into an argument with a man. ( Supplied )

Esmaili 'diagnosed with psychiatric illness'

Police said it was possible Esmaili and Dr Pritzwald-Stegmann had argued about smoking near the hospital before the alleged assault.

The court heard Esmaili had recently been dependant on drugs and had been diagnosed with a psychiatric illness.

The prosecution said the entire encounter was captured on CCTV.

Magistrate Suzie Cameron ordered a medical assessment of Esmaili.

Eastern Health said Dr Pritzwald-Stegmann was stabilised at the hospital at the time of the incident, before being taken to The Alfred hospital in a critical condition.

Police said he was still in hospital this morning, but did not provide an update on his condition.

Esmaili has been remanded in custody and will return to court on August 24.