The Australian police officer who shot a Queensland woman in the eye with a stun gun is a qualified Taser instructor.
The 29-year-old woman has undergone emergency surgery after the stun gun's metal prong hit her in the eye as police tried to restrain her on Thursday.
Police say the woman was tasered after she threatened officers with a table leg that had nails sticking out of it at her home at Logan, south of Brisbane.
The officer who deployed the weapon is now the subject of an Ethical Standards Command investigation.
Police service guidelines on Taser use specifically warn of the risk of eye injuries.
"Tasers should not be aimed so as to strike the head or neck of a subject unless this is unavoidable," the guidelines say.
The woman's family has told the ABC she has lost her eye.
The hospital where she's being treated said the woman was in a stable condition, but would not confirm her injuries.
Acting Assistant Commissioner Steve Hollands said the officer who deployed the stun gun was a very experienced senior constable.
"He's also a qualified Taser instructor," he told the ABC.
"The Ethical Standards Command and the Criminal Investigation Commission will overview the matter. At this point in time, the woman remains in hospital."
Police were to hold a press conference about the incident later in the day.
An unnamed woman has told the ABC it was her sister who was shot.
She said her sister had become upset during a visit from social workers, prompting an ambulance and police to arrive. Then the weapon was deployed.
"The Taser was in her eye and she was in so much pain she said to the police officer 'the Taser's in my eye, the Taser's in my eye' screaming all the while," the woman said.
"The police officer came to the ambulance to speak to (my sister) and said 'I know you probably don't want to speak to me right now but I am sorry'."
A neighbour who witnessed the incident, but did not want to be named, said the woman was shot when she was about five to seven metres away from officers.
"I doubt a tasering was necessary," he told the ABC.
Aboriginal activist Sam Watson has called on police to hand in their Tasers until the matter has been investigated.
"The Queensland Police Service just cannot be trusted with these Taser weapons," he told the ABC.
"They are very dangerous. They can cause permanent damage as we've seen."