A pitbull-type dog that killed Canberra woman Tania Klemke at her home in the early hours of Wednesday morning had attacked a person before, the ACT Government has confirmed.

The animal was shot dead at the Watson house by police just before 4:00am after neighbours heard a man calling for help.

When officers arrived the injured man took them inside to Ms Klemke, who had suffered severe injuries from the attack.

"While CPR was being performed on [Ms Klemke], the dog moved to attack the police officers, and in order to protect themselves there was a necessity to discharge the firearm," Detective Acting Superintendent Tony Crocker said.

Ms Klemke died of her injuries and the man was taken to hospital in a stable condition with a bite mark to his leg. No police were injured.

Ms Klemke was attacked and killed by her own dog in the early hours of Wednesday morning. ( Supplied )

Ms Klemke's son, Cody Baker, in a statement paid tribute to his mother as a kind, caring woman.

"She had the biggest heart and always did anything that she possibly could for the people she loved and cared for," he said.

City Services Minister Meeghan Fitzharris confirmed the dog was previously known to the ACT Government.

"I can't speak for ACT Policing, but I can speak for Domestic Animal Services, and my advice today is that on one previous occasion they did attend that household at the request of ACT police," Ms Fitzharris said.

"The dog was known to the directorate, and I understand that took place in late August.

"I understand that someone may have been injured, and I also understand that the dog may have been injured in that attack as well."

A man is in hospital in a stable condition. ( ABC News: Ian Cutmore )

Ms Fitzharris said she understood the dog lived in the home with Ms Klemke.

"Clearly the dog was dangerous, clearly the dog has attacked someone overnight, someone we understand to be its owner or carer," she said.

Police are investigating and a report will be prepared for the ACT coroner. The injured man is assisting police with their investigation.

Liberals demand answers

Canberra Liberals' leader Alistair Coe called for more information to be released to the public.

"I think the public really needs to have a good understanding of the facts of this matter," he said.

"We want to know what the circumstances were surrounding the attack.

"There are many serious questions that need to be answered — there is of course a legal process we've got to contend with as well, but I believe there is some information that can be presented and we will be working with the Police Minister's office to see what facts can become available to the public."

Mr Coe said the death reinforced the Liberals' concerns over current laws regarding dangerous dogs.

The Opposition is preparing legislation to try to force new laws, which include tougher restrictions on dogs that have previously attacked being released back into the community and tighter penalties for owners of dangerous dogs.

ACT Greens leader Shane Rattenbury agreed there was "room for improvement" with the ACT's dog laws but reaffirmed his opposition to banning dogs based on perceived "dangerous breeds".

Ms Fitzharris previously said the ACT Government had not ruled out potential legislative changes or higher fines for dangerous dog owners.