The site near the Sydney Opera House in Australia was cleared and a police search operation was conducted on Thursday.
Several ferries in the area were also cancelled, according to The Sydney Morning Herald.
The New South Wales police said in a statement that the search was done as a 'precautionary measure' based on information on social media. The police operation has concluded, the statement said.
Fairfax Media reported that a bomb threat on a ferry sparked an alert.
Australian police have carried out several anti-terror raids in recent months, citing threats from home-grown militants.
The New South Wales official ferry service said on Twitter that some ferries had been cancelled while others were delayed due to the police operation at the Sydney Opera House.
The 1:20pm Manly to Circular Quay ferry has been cancelled due to a police operation at Manly. Passengers can catch the 1:40pm service.— Ferries Info (@FerriesInfo) January 14, 2016