Circular Quay has been reopened after earlier being evacuated when police were alerted to a possible suspicious object on a ferry.

Ferries, trains and buses were disrupted, and an exclusion zone was established in the area, for about 90 minutes, until police announced that the package had been deemed not suspicious.

Specialist police, three fire trucks and a rail emergency response truck were on the scene during the scare. Reports of navy vessels responding were incorrect, as they were nearby undertaking independent harbour training.

A NSW Police spokesman said he understood that no people were in the vicinity of the ferry, called the Friendship, which was docked at wharf 5B.