An Australian police officer is to face charges for firing a stun gun at a 95-year-old woman, leaving her with critical head injuries, as she approached him while using a walking frame and carrying a steak knife in a nursing home.

Clare Nowland, who has dementia, is receiving palliative care in hospital in Cooma, New South Wales.

She fractured her skull in a fall on Wednesday last week after Constable Kristian White shot her with a stun gun in her retirement home.

The violence against an elderly and incapacitated woman has sparked a national debate about the police use of stun guns in such circumstances and the competence of care staff.

Police are allowed to use stun guns when lives are in danger.

White was ordered on Wednesday to appear in court on July 5 on charges of recklessly causing grievous bodily harm, assault occasioning actual bodily harm and common assault.

The charges are likely to be upgraded as she is expected to die of her brain injuries.

White has been under police internal investigation since the incident and has been suspended from duty with pay since Tuesday.