The 34-page document issued by the Port Authority of New York and New Jersey, which owns the site, stated that ‘the schedule and costs for each of the public projects on the site face significant delays and cost overruns’.
According to the report, the main problem with the redevelopment was overly ambitious completion dates, which were inaccurate from day one.
It is believed that delays could run for up to three years, while costs could balloon to more than $15 billion (£7.5 billion).
The document also stated that Santiago Calatrava’s $2.5 billion (£1.25 billion) PATH station and transit hub, as well as being over budget and behind schedule, will also have to be redesigned.
Speaking to the New York Times, Port Authority director Christopher Ward said: ‘The question surrounding the World Trade Center rebuilding is not if all of the projects will be built, rather when and for how much.’