Aussies have been left divided over calls for a shark cull after a mother was mauled at a beach, left fighting for her life, and had her arm amputated. 

Leah Stewart, 35, was 30m from the shore at Coogee beach, in Sydney's eastern suburbs, when she was attacked by a great white shark on Saturday morning. 

A friend was looking after her one-year-old daughter on the beach at the time. Her husband was overseas but has since rushed back to Australia to be by her side.

Off-duty lifeguard Charlie Verco, 25, grabbed her to safety on his paddleboard and paddled her to shore as she was losing consciousness.

Ms Stewart was airlifted to St Vincent's Hospital in a critical condition.

Former prime minister Tony Abbott has led calls for a shark cull, arguing it is 'so wrong that we don't put people before sharks'. 

Premier Chris Minns has not ruled out enforcing one, while promising to invest in AI drones that can surveil the beach for great white or bull sharks.

Aussies have been left divided over a push for a cull, with many saying it is a necessary measure. 

'Too many attacks, their numbers are increasing and they are coming in closer. I used to love a bodysurf, wouldn't do it now,' one wrote.

'Humans must remain as the apex species of this world despite what the greenies and wokies that will complain. I say WE MUST CULL,' a second said.

Others felt the sea predators should be left alone. 

'Leave the sharks alone, we are going into their environment, they are not coming into ours,' one wrote. 

'If sharks came on land and started attacking I'd be all for culling, but when we're entering their territory we accept the risk,' a second added. 

'Absolutely not! They balance the marine ecosystem. As humans entering the water in Australia you have to be aware that when you go in [the water], you don't know if you'll get out,' a third said. 

On Monday, Ms Stewart's brother Joshua revealed the extent of her injuries in a GoFundMe campaign.

He described her injuries as 'severe' and 'life-threatening'.

'She has multiple bites across her arms and legs, lacerations and fractures throughout her body, and extreme blood loss,' he wrote.

'Leah remains in a critical condition on life support and has undergone multiple surgeries in the days after the attack.

'Tragically, her treatment has required the amputation of her arm, and more surgeries are scheduled for the coming days.'

He said her recovery would be a long process and all donations would go towards rehabilitation, prosthetics and improving her quality of life.

Mr Stewart said his sister was swimming between the flags and close to the shore when the shark attacked.

He thanked the first responders who helped save her life.

Mr Verco was paddleboarding about 100m from Ms Stewart when the attack occurred.

He immediately paddled towards Ms Stewart and the shark and lifted her out of the water.

'The water got very bloody and she got taken under and after a few seconds, popped up again and the shark had let her go,' he told ABC News.