A police operation took place at Sydney Opera House with some ferry services cancelled and reports of an evacuation.
As the operation concluded about 3.45pm, a NSW Police statement said it was based on information on social media.
"Following information on social media, police conducted an operation in the vicinity of the Opera House and Manly as a precautionary measure," the statement said.
A Sydney Festival spokesperson told HuffPost Australia tonight's show Cut The Sky was going to go ahead as planned at Sydney Opera House.
During the operation, a Sydney Opera House employee commented on social media and news site Reddit saying “I’m inside the Opera House as an employee, there is no news for staff either just that a security threat was received and police operation is under way”.
Police also confirmed a second operation was underway at Manly and one ferry service was cancelled but that also concluded.