The attacker is not known to the police, and the motive is not clear, police said, adding that they were carrying out a critical incident investigation and had not ruled out terrorism as a motive.
The large, upscale shopping mall is situated in the affluent Eastern Beaches area of Sydney, less than two miles from Bondi Beach.
Australian Prime Minister Anthony Albanese said he had been briefed on the incident, writing on social media: “Tragically, multiple casualties have been reported and the first thoughts of all Australians are with those affected and their loved ones. Our hearts go out to those injured and we offer our thanks to those caring for them as well as our brave police and first responders.”