A six-year-old boy and a man in his thirties have died after a holiday home north of Melbourne went up in flames.
Emergency services were called about 11:40pm on Saturday to the home in Tyaak, near Broadford, about 95 kilometres north of Melbourne.
The first fire truck arrived 20 minutes after it was called.
The inferno was described by a witness as a "wall of flame" and neighbours in the small locality tried to extinguish the fire with buckets of water.
It is believed 13 people were staying at the holiday property for the Queen's Birthday long weekend and at least eight people were taken to hospital with injuries.
It is unclear if they were asleep when the fire broke out.
Victoria Police said a six-year-old boy and a 33-year-old man died at the scene.
Police earlier said a 34-year-old man later died in hospital, but later issued a correction saying the man was still alive in a critical condition.
The fire is under investigation by the Arson and Explosive Squad.
Sergeant Daniel Raynor of Seymour Police Station said it was a "traumatic incident".
"At this stage, Victoria Police are currently investigating the cause of the fire," he said.
"Especially for the family members, it's extremely tragic circumstances for them."
Three people are being treated at The Alfred hospital, including two women in their 30s who are in a serious but stable condition and the 34-year-old man who is critical.
Five children are being treated at the Royal Children's Hospital, four of whom are in critical condition.
At least two are infants and two are school-aged children.
CFA commander Charles Cleary said 14 fire appliances were sent to the property, with a number of other support vehicles.
"There were quite a number of individuals who were at the property," he said.
"It took approximately an hour and a half to get the fire under control."
The small locality of Tyaak, just off the Hume Freeway, had a population of just 73 in the 2016 Census.
The exact circumstances surrounding the blaze are still being determined and anyone with information is urged to contact Crime Stoppers.
