A former nurse who deliberately lit two fires at a Sydney nursing home has pleaded guilty to 11 counts of murder.

The four-week trial of 37-year-old Roger Dean was due to start in the New South Wales Supreme Court today.

He was charged days after the fire which ripped through the Quakers Hill nursing home in the early hours of November 18, 2011.

Dean previously entered guilty pleas to two counts of larceny for stealing painkillers, and prosecutors previously rejected his guilty pleas to manslaughter charges.

Family and friends of some of the victims were in court today to see him change his plea to guilty to the murder charges.

Dean has also pleaded guilty to eight counts of recklessly inflicting grievous bodily harm.

Relatives of the victims cried in the public gallery as the pleas were entered.

Outside court Elly Valkay, whose mother Neeltje Valkay was killed, said the guilty pleas were the best outcome.

Victims of the Quakers Hill nursing home fire: Dorothy Wu, 85

Alma Smith, 73

Reginald Green, 87

Lola Bennett, 86

Ella Wood, 97

Urbana Alipio, 79

Caesar Galea, 82

Doris Becke, 96

Verna Webeck, 83

Dorothy Sterling, 80

Neeltje Valkay, 90

"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," she 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'."

Ms Valkay says she had been very close to her mother.

"I saw her six days a week," she said.

"I still do the wrong left hand turn to go home and go past the nursing home.

"There has been upheaval in our family because we miss her so much. There has been nights of no sleep...I still have nightmares."

Dean will be sentenced by Justice Megan Latham at a later date.

There were more than 80 residents in the home when the fire started in the early hours of the morning.

Some victims died during the fire and others after it as a result of their injuries.

Sorry, this video has expired Jamelle Wells reports on Sydney nurse Robert Dean's guilty plea

Emergency crews were at the scene quickly and, although the home had fire extinguishers and fire doors, it did not have sprinklers in place.

It is now compulsory for nursing homes in New South Wales to have sprinklers.

Gary Barnier, Managing Director of the Domain Principal Group which owns the Quakers Hill home, says much has been been learnt from the tragedy.

"Fire sprinklers are now mandatory in New South Wales and we're just finalising the completion of those right round the country," he said.

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