A section of Sydney's CBD shut down following reports of a bomb threat at the multibillion-dollar Barangaroo construction site has been reopened.

Police gave the all clear for the east Darling Harbour site just before midday Monday, with all roads reopened and workers allowed to return.

Construction workers leave the site. Credit:Nick Moir

Hickson Road had been closed in both directions between Towns Place and Napoleon Street after the threat was received at 10am Monday. The affected area was then extended further south to the corner of Sussex Street and Erskine Street

Construction workers were also evacuated from the site immediately following the threat.