It's the first reported shark attack since January, when a 12-year-old boy died after an attack in Sydney Harbour.

The woman attacked by a shark in Sydney Harbour and her family have released a statement sharing details of the attack, which left her with critical injuries. Lauren O’Neill, 29, was set upon by the ocean predator in waters off Elizabeth Bay just before 8pm on Monday.

A St John Ambulance Western Australia spokesman says the incident took place off Rottnest Island near Perth.