SYDNEY - An Australian police officer and a security guard are in a critical but stable conditions after an alleged confrontation with a man who was threatening doctors with scissors at a local hospital.

Local authorities on Wednesday said a New South Wales Police officer and a security guard were both shot in the leg following an altercation with a man who grabbed the officer's gun at Penrith Hospital in Sydney's Western suburbs late on Tuesday night.

Unconfirmed media reports suggest the man held scissors to a female doctor's throat after she had intervened in an argument before the police and security officers had arrived to resolve the situation.

New South Wales Police deputy commissioner Catherine Burn told reporters outside the hospital on Wednesday the officer who was shot in his left thigh is in a "critical but stable condition", and the incident is not terror-related despite some commentary suggesting otherwise.

"(Police) are looking at other issues at play in this story," Burn said.

A police spokesperson could not confirm to Xinhua if the 39-year-old alleged attacker, who has been arrested on a series of charges including intent to murder, was under the influence of drugs.

The security guard was shot in the calf and remains in a stable condition.

Australia's Health Services Union (HSU) secretary Gerard Hayes said the latest incident is just another in a string of attacks against security guards at hospitals as they handle violent patients and visitors.

"We have been calling for more powers for hospital security officers for several years but the government has refused to do anything more than instruct our members to call the police in the event of problems at hospitals," Hayes said in a statement.