The cost to Greece of hosting the 2004 Olympic Games came in at 9bn euros ($11.6bn; £6.3bn), double the original target, the government said.
The Athens Olympics won praise but caused economic pain
"There is a huge overrun in relation to original estimates," said finance minister Giorgos Alogoskoufis.
Greece is struggling to trim its budget deficit, which breaches European Union limits and has earned an EU rebuke.
The finance minister said the final cost of organising the 2004 Games - the most expensive ever - could go higher.
More to come?
He said 9bn euros was "the immediate cost for the state and does not include expenditures for infrastructure".
ATHENS 2004 - WHAT IT COST
Security - 1bn euros
Sports venues, equipment - 2.1bn euros
Infrastructure - 2.8bn euros
Athletes hospitality, other costs - 1.1bn euros
It excludes projects such as the new airport and a high-speed tramline linking the airport to central Athens.
Greece originally budgeted 4.6bn euros ($6bn; £3.2bn) for the games, compared to a budget of roughly $2bn (£1bn) for the 2000 Olympic Games, hosted by Sydney, which also suffered from cost overruns.
Heightened security fears after the 9/11 attacks added unforeseen costs after Athens won its bid to become host city.
Construction delays also pushed up costs, leading to a hasty and expensive last-minute push to get venues ready in time.
Greece's tourism industry did not reap the hoped-for rewards from hosting the games. Government estimates have suggested visitor numbers could be as much as 10% down on 2003. Fears about security and price gouging appear to have kept visitors away.
The government is trying to control its budget deficit through a mix of privatisations and public spending cuts.
EU states are expected to have deficits below 3% of gross domestic product, but Greece's deficit is set to hit 5.3% in 2004.
In May 2004, the EU branded Greece's budget deficit "financially imprudent".
Greece's deficit breached the EU 3% cap between 2000 and 2003.