A leading Greek think tank has accepted a commission from the former chief of the Athens 2004 Olympics to study the event's true cost, deemed the most expensive ever at the time.
"Ten years after the Games...(we are) undertaking a study into the imprint which the 2004 Olympics had on the Greek economy," the foundation for economic and industrial research (Iove) said in a statement.
"Until now, there has been no detailed, scientific investigation of their overall impact," the state-supervised foundation said.
The study, to be released before the end of the year, was commissioned by former Athens 2004 organising committee chief Gianna Angelopoulos-Daskalaki.
Marked by extensive delays that caused huge cost overruns, the Athens 2004 Olympics spearheaded a radical infrastructure makeover but also left behind a host of expensive sports venues that Greece never managed to fully utilise.
Last year, the finance ministry said 8.5 billion euros ($A12.75 billion) had been spent on the Olympics, but the bill included non-sports infrastructure such as archaeological sites and hospitals.
The finance minister said out of that total, the sum of 2 billion euros ($A3 billion) had been covered by ticket sales, TV rights and sponsors.
However, the actual cost of the Games is believed to be around 13 billion euros ($A19.5b), including an estimated one billion euros spent on security after the Al-Qaeda attacks on the United States in September 2001.
Greece nearly went bankrupt in 2010, and former International Olympic Committee chief Jacques Rogge in 2011 said the Games "played a part" in fuelling the country's enormous debt.
"If you look at the external debt of Greece, there could be up to two or three per cent of that which could be attributed to the Games," Rogge told Greek daily Kathimerini.
But the competition "could have been staged at a much lower cost, as there were delays that rendered double shifts necessary, and having people work at night does cost more", Rogge said at the time.
