Woman in critical condition after shark attack at Sydney's Coogee Beach

A woman is in a critical condition after being bitten by a shark at a beach in Sydney's east.

Emergency crews were called to Coogee just before 11:15am on Saturday after members of the public pulled a woman, believed to be in her 30s, from the water.

She was treated for serious leg and arm injuries, with preparations underway for her to be flown to hospital.

ABC journalist Patrick Stack was at the beach playing with his child in the water on a "beautiful winter's day" when the attack took place.

He described what played out as "extremely concerning".

"Lots of people [were] swimming in the water when we heard a really chilling scream going out across the beach," Mr Stack said.

"And at first you wonder whether it's sort of kids mucking around or something like that. 

"But the quick follow of the shark alarm sort of made it clear that it was something much more serious and much more sinister."

He said he was about 50 metres away from where the woman was pulled from the water by a man on a surf rescue boat with  help from a paddle board rider.

The community, according to Mr Stack, is very tight-knit and the majority of people at the beach were familiar faces.

He said they have been left in "stunned silence".

"In winter, it's not peak sort of tourist season, so it's very familiar faces all down here to do their weekend swim and hearing local swimmers floating around nearby saying that they saw a shark swim underneath them. 

"Obviously eerie sort of scenes and lots of distress amongst the community and not what you sort of expect when you come for your Saturday swim at the beach."

Coogee Beach along with others in the Radwick Council area have been closed.