Most Olympic host cities make money from running the Games -- Athens in 2004 reported an initial operating profit of $155 million -- but the bills for building stadiums and other infrastructure can take many years to pay off.

The state audit office said the profit was more than double the most recent estimate of 410 million yuan.

Operating revenues totalled 20.5 billion yuan, mainly from broadcasting rights, sponsorship, merchandise and tickets.

Expenses were 19.3 billion yuan, including 5 billion yuan for broadcasting, accommodation, transport and medical services; the opening and closing ceremonies cost 831 million yuan.

The audit office said the Beijing Organising Committee for the Olympic Games (BOCOG) had kept good control of revenues and expenditure "with no major irregular problems".

Arriving at a final price tag for the Games would involve calculating the cost of closing thousands of factories to ensure clean air during the Games, offset by the value of the international publicity the Olympics generated.