Four children feared dead in NSW fire

Wyong, NSW - Fire crews are struggling to reach the top floor of a house where it is feared four children have perished in an early morning blaze on the NSW central coast.

Three other children who escaped the flames have been taken to Gosford Hospital with severe smoke inhalation.

Emergency services were called to the blaze at a house in Wyong just after 2am.

The blaze has severely weakened the two-storey house and a search for the missing children has been hampered by fears the roof could collapse.

"The fire has been extinguished but the premises are still unstable -- too unstable for anyone to enter the top floor," NSW Police Superintendent Kim Sorensen told the Nine Network.

He said fire crews were using ladders to try to see into the upstairs bedrooms.

"I've had no report from them as to their findings at this stage."

Supt Sorensen said fire crews found the three surviving children at the front of the house, which was well alight when officers arrived.

"After rendering first aid to the children that were there, (the fire fighters) started an aggressive attack on the flames, but because of the ferocity of it they were driven back," he said.

He said the three children were extremely traumatised.

"Their condition basically was that they were suffering severely from smoke inhalation and obviously suffering from enormous stress," Supt Sorensen said.

It is not known if the seven children are related.

Early media reports have said the four children feared dead were believed to be aged one, three, and two aged seven.

Supt Sorensen would not comment on whether any adults were in the house with the children at the time of the fire, which broke out about 2am (AEST).

That's part of the ongoing investigation into this matter and that will form part of the brief we prepare for the coroner," he said.

Supt Sorensen said the town would be shocked by the desperately sad situation.

"It's tragic for everyone involved -- obviously for the relatives, for bystanders around here, and for the emergency services that have had to attend."

There was no early indication of what might have caused the fire.

The fire is the third fatal blaze in NSW this week.

A farmhouse fire at Coonamble on Sunday claimed the lives of Tony and Belinda Conn and one of their four-year-old twin sons.

The couple ran back into the burning home to try to save their son but perished in the flames. Their other three children survived and made a long trek in darkness to raise the alarm.

And yesterday, a man and a woman were found dead in a smoke-filled farmhouse near the village of Burraga in the NSW central tablelands.

- AAP