“The court of auditors has temporarily blocked the signature of the sale agreement,” Greek development fund Lamda said in a statement.
The Greek state privatisation agency would contest this ruling in order to permit the investment to proceed, Lamda added.
Situated eight kilometres (five miles) south of Athens, the former airport of Hellinikon and an adjoining 337-berth marina span nearly 620 hectares and include a waterfront of about 3.5km.
In March, a consortium comprising Lamda, China’s Fosun Group and Abu-Dhabi property firm Al Maabar landed a 99-year lease for Hellinikon at a price of $1.18bn.
But this week, the state court of auditors found that the sale tender for Hellinikon had set unduly restrictive criteria for the participation of investors.
The Lamda consortium has pledged to invest €5.9bn over the next 15 years to create parks, leisure, exhibition and concert facilities, hotels and luxury residences at the site.
Under the terms of the deal, the Greek state has two years in which to complete the cumbersome land permit procedure or the investors are free to walk away from the project.
Hellinikon was turned into a sports complex for the 2004 Olympics, but most of the venues built for the Games have rarely been used since.
It was put on sale in December 2011 the Lamda consortium was the only remaining bidder after other investors from Britain, Israel and Qatar pulled out.