He was supposed to take care of the elderly and infantile, but the reversed happened almost two years ago. Nurse Roger Kingsley Dean, who initially said the blaze that gutted down Quakers Hill nursing home in Sydney was an accident, on Monday pleaded guilty to the murder of 11 elderly people.

Dressed in a black suit and blue tie, with head bowed down, admitted to starting the fire on November 18, 2011 in two parts of the building. In a soft and solemn tone, he pleaded guilty to 11 counts of murder and eight charges of recklessly causing grievous bodily harm.

The victims were identified as Dorothy Wu, 85 and Alma Smith, 73, who both died at the scene; 87-year-old Reginald Green; Lola Bennett, 86; Ella Wood, 97, Urbana Alipio, 79, Caesar Galea, 82, Doris Becke, 96; Verna Webeck, 83; Dorothy Sterling, 80, and Neeltje Valkay, 90, who all died in various hospitals after the fire.

Moreover, Mr Dean also pleaded guilty to stealing drugs from the home.

Mr Dean's trial is expected to last for three months following an earlier plea of not guilty. Justice Megan Latham will sentence Mr Dean at a later date.

At the height of the fire, Mr Dean even boasted to Australian television cameras and crews of how he rescued several residents, which totaled to more than 80 residents. Some of the victims died during the fire. Others died several days after as a result of their injuries.

Relatives of the victims cried in jubilation outside court.

"It wasn't happiness of course, I still miss my mother very much and the rest of our family miss her greatly, especially her grandchildren," Elly Valkay, whose mother Neeltje Valkay was killed, said.

"It was, I think, joy in my heart to see that my mother would say 'yes justice is going to be done and we're going to see it'."

The November 2011 blaze had prompted Australia's NSW government to revisit laws and policies governing such institutions. Emergency crews who responded to the scene said the place did not have sprinklers in place, although the home had fire extinguishers and fire doors.

NSW had ordered all nursing homes to install sprinklers.

"Fire sprinklers are now mandatory in New South Wales and we're just finalising the completion of those right round the country," Gary Barnier, Managing Director of the Domain Principal Group which owns the Quakers Hill home, told ABC News.

"We'll continue to learn and to try to make sure something like this never ever happens again."