NSW Health Minister Jillian Skinner has convened an urgent meeting to discuss upgrading security in the state's hospitals after an ice-crazed patient allegedly attempted to shoot dead a police officer.

Michael De Guzman, a 39-year-old registered nurse, allegedly held a pair of scissors to the throat of a female doctor in Nepean Hospital's emergency department on Tuesday night, screaming that he was "gonna kill" following an argument with his wife.

The ice-addicted patient, who had been admitted to the hospital's emergency ward twice throughout the day, then scuffled with a police officer and a security guard, allegedly shooting both men when he tried to grab the officer's gun from its holster.

Senior Constable Luke Warburton, a decorated Dog Squad officer who was instrumental in the arrest of notorious fugitive Malcolm Naden, was hit in the upper thigh in front of terrified patients and staff just before 10.30pm.

He remained in a serious condition on Wednesday night. The security guard, 48-year-old Barry Jennings, was hit in the calf and remained in a stable condition.

The incident prompted the Health Services Union to warn that security in NSW hospitals is under-resourced and ill-equipped, particularly in the face of a growing ice epidemic.

"The ice situation is really getting out of control, particularly in emergency departments," said HSU secretary Gerard Hayes. "We're seeing a growing number of violence issues. This needs to be addressed."

Mrs  Skinner agreed to the union's request to meet urgently next week to discuss hospital security.

The union will demand that guards be equipped with handcuffs and powers to restrain or detain violent patients. At the moment, guards can only "observe and report". They will also ask for a summit regarding safety and security in NSW hospitals.

Fairfax Media has been told Mr Guzman, a registered nurse who left Westmead Hospital two years ago, had never come into contact with police until a bizarre 24-hour episode on Tuesday.

Earlier in the day, he was arrested for an aggravated break and enter in Colyton and was also charged with assaulting two police officers and resisting a third officer.

Officers took him to Nepean Hospital in police custody but later returned to serve a court attendance notice on him while in hospital, with the only bail condition being that he stay away from an address in Colyton.

Mr Guzman was discharged but returned later on Tuesday with more injuries, including a suspected broken jaw.

Nearby patients said they could hear him embroiled in an argument with his wife that spilled over into the emergency department ward.

There was about 10 minutes of yelling and screaming before two shots were fired from Senior Constable Warburton's gun.

An elderly male patient, who was about to go to sleep in a neighbouring room, said he could hear the man screaming "I'm gonna kill you. I'm gonna kill you" and "you took my family".

Another patient who heard the fight said the man's wife was among several people who kept screaming "Michael, Michael" at him.

"When the first shot went off, the woman let out this deafening scream. It was horrible. Then when the second shot went off she screamed even louder," the patient said.

Fairfax Media has been told Senior Constable Warburton was hit in the femoral artery and would have died if he wasn't already in an emergency ward. Patients described horrifying amounts of blood pooled on the hospital floor.

"It looked like enough blood to kill somebody," one patient said. "It looked like something from the movies. There was blood spatter on the walls."

Mr Guzman has been charged with shooting with intent to murder, discharging a firearm to resist arrest and detaining for advantage.

He was due to appear in Penrith Local Court on Wednesday but had to be taken back to Nepean Hospital for further assessment.

Mr Hayes said hospital employees are facing such violence every day.

"We're seeing more and more violent issues, we're seeing more security officers injured," he said. "We've been calling on the government for some time to have a summit to deal with this."

In September, the riot squad were called to RPA hospital following a brawl in the geriatric department that left a nurse and two security guards injured.