Police say the victim, a 47-year-old patient transport officer from Pakenham, was standing outside the hospital on David Street about 3.30pm on Tuesday when he was approached by three men.

One of them asked him for a cigarette and he refused.

The men then argued with the victim, knocking him to the ground.

He was then "kicked numerous times" while on the ground, a police spokeswoman said.

A passerby came to his aid, as did one of the man's colleagues, who suffered some minor scratches and bruising during the incident.

The three offenders fled the scene..

It is understood the man was having a cigarette while on a 10-minute break when he was assaulted.

A Monash Health spokeswoman said the victim and his colleague were treated in the hospital's emergency department, and both were discharged on Tuesday night.

'Why would I feel safer?'

A Melbourne surgeon who was stabbed 14 times by a patient in 2014 at the Footscray hospital says the incident in Dandenong was more proof that work to improve hospital security had failed - and that hospitals were becoming more dangerous.

Neurosurgeon and spinal surgeon Dr Michael Wong said that, more than three years after he was attacked, he felt less safe at work now than ever.

"Why would I feel safer? Three months ago a surgeon in Box Hill was killed on the job, so it doesn't exactly back that up," Dr Wong said.

"Whatever may have been done since my attack hasn't had any effects ... if it had, [Box Hill heart surgeon Patrick Pritzwald-Stegmann] would not have died.

"If anything it's getting worse."

Dr Wong is calling for a number of measures to make hospitals safer, saying policy announcements to date are "window dressing".

Among his recommendations, is to permanently place security guards in busy public areas of hospitals, rather than having them on call to respond to incidents.

"What we need is not a reactionary system, one where normally no [security guards are] there and when you ring the alarm they answer," he said.

"That is simply not working."

Dr Wong also wants separate hospital entries for staff and the general public and for fewer areas of hospitals to be open to the public.

"Mentally ill patients tend to gather around the foyer and, if for some reason, they have something against a staff member, they think they just have to wait there and come and beat you up," he said.

'It's unacceptable'

The man injured in the latest attack works for the National Patient Transport Group, which transports patients for Ambulance Victoria.

The group sent an email to staff on Tuesday night about the incident.

Chief executive Jeff Wilson said his "primary concern" was for the wellbeing of their employee.

"Our focus is on his wellbeing, and we've set up some counselling for them," Mr Wilson said.

"Our staff are in the public all the time, doing their duty, and they do see things that shouldn't happen.

"We've put a note out for all our staff, and we've encouraged staff to use peer support to talk about the issues that can happen and the impact on them."

The union representing patient-transport officers, Ambulance Employees Australia Victoria, claimed the officer was on standby outside the hospital when he was attacked.

Union secretary Steve McGhie said the attack highlighted concerns about transport officers being stationed outside hospitals.

"While they're on standby they are easy pickings for people who want to have a go at them."

But Mr Wilson said the attack had occurred outside hospital property during the employees' 10-minute break.

Staff had access to facilities in all major hospitals and were never told to wait in carparks, he said.

Martin Foley, Victoria's Minister for Mental Health, said the government had "zero tolerance for violence, abuse and aggression against any Victorian especially our hardworking healthcare workers".

"We are working with health services and supporting them to develop tailored solutions, whether that is duress alarms for staff, trialling body cameras for paramedics, or stab-resistant vests for security workers," he said.

The attack comes about three months after heart surgeon Patrick Pritzwald-Stegmann was attacked at Box Hill Hospital in allegedly similar circumstances.

It is believed that Mr Pritzwald-Stegmann was punched in the face and knocked unconscious after talking to two people he saw smoking in the hospital foyer.

Mr Pritzwald-Stegmann, a father of two, spent four weeks in intensive care at The Alfred hospital after undergoing emergency brain surgery. He died of his injuries on June 27.

A Mill Park man, 22, is due to face court on September 22 over the Box Hill incident.

He was initially charged with intentionally and recklessly causing serious injury, but that charge has since been upgraded to manslaughter.

There were 8627 reports of violence within Victoria's public hospitals in the 12 months to June 2016.

The state government has announced funding to build safe rooms for emergency department staff, and promised $40 million for greater security at public hospitals, such as increased CCTV coverage and behaviour assessment rooms for aggressive patients.

With Robyn Grace