Emergency services have responded to a house fire in Marsfield, with four people treated for either smoke inhalation or severe burns.
Paramedics received the call just after 4pm and arrived at the scene on Zanco Road within minutes.
A male in his 40s was unconscious upon arrival. He has 70 per cent burns and was treated on the scene by CareFlight.
He has been taken to Royal North Shore Hospital in critical condition.
A 29-year-old woman has also been taken to RNS Hospital with 70 per cent second degree burns.
She is also in critical condition.
A girl aged approximately eight years old also sustained burns and smoke inhalation.
She was taken to Westmead Children's Hospital in a serious but stable condition.
A fourth adult, male, was also at the scene but denied further treatment. He suffered smoke inhalation.
A crime scene has been established and the cause of the fire is yet to be determined.