An Australian nursing home resident is in critical condition after being stunned by a Taser and collapsing to the floor.

An Australian police officer is under investigation after firing a Taser at a 95-year-old woman with dementia inside a nursing home.

The incident occurred on Wednesday morning at a nursing facility in Cooma, a small town about 250 miles south of Sydney. Two New South Wales police officers responded to a call that an elderly patient, Clare Nowland, had taken a serrated-edge steak knife from the kitchen, according to NSW assistant police commissioner Peter Cotter.

The officers found Nowland, who is 5-foot-2, alone inside a small treatment room and asked her to drop the knife "for a number of minutes." Nowland did not do so and moments later, an officer stunned Nowland with a Taser, Cotter said.

The woman subsequently fell to the ground, sustaining a head injury. As of Friday morning, Nowland remains in Cooma Hospital, where she is in critical condition, Cotter added.

"We the police treat this matter with extreme significance," he said in a press conference on Friday.

An internal investigation has been launched into the officer in question, who was a senior constable with 12 years of experience. The officer, whose name was not released by police, has been transferred to "nonoperational" duties.

It is unclear if the officer will face criminal charges, but Cotter said no officer is "above the law."