Twenty Sydney beaches have been closed indefinitely, following a third shark attack within 24 hours. 

A surfer is in a critical condition with serious leg injuries, after being bitten at North Steyne Beach at Manly in Sydney's north last night.

It happened a matter of hours after an 11-year-old surfer had his board bitten by a shark a few kilometres away at Dee Why - and a 13-year-old boy was attacked while swimming on Sunday.

Australian correspondent Murray Olds says experts have raised concerns about adverse weather conditions luring in the sharks, putting people at risk.

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Twenty Sydney beaches have been closed indefinitely, following a third shark attack within 24 hours.&nbsp;
A surfer is in a critical condition with serious leg injuries, after being bitten at North Steyne Beach at Manly in Sydney's north last night.
It happened a matter of hours after an 11-year-old surfer had his board bitten by a shark a few kilometres away at Dee Why - and a 13-year-old boy was attacked while swimming on Sunday.
Australian correspondent Murray Olds says experts have raised concerns about adverse weather conditions luring in the sharks, putting people at risk.
LISTEN ABOVE

With a straight down the middle approach, Heather du Plessis-Allan Drive on Newstalk ZB delivers the very latest news and views to New Zealanders as they wrap up their day.

Heather du Plessis-Allan Drive

Murray Olds: Australian correspondent on the string of shark attacks closing Sydney beaches

https://api.omny.fm/orgs/7784f840-c291-422a-924b-ad9000bbad71/clips/c4d4e60f-a0a5-4898-83d7-b3d8004d7aa9/transcript