The Olympic stadium for the 2012 Games will cost £216m more to build than originally predicted, the Olympic Delivery Authority (ODA) has said.
Artists impression of the 2012 Olympic Stadium
While bidding for the Games the projected cost was £280m but since then the figure has risen by more than 77%, the new ODA chairman John Armitt said.
He said "inflation, VAT, legacy conversions and earthworks" had resulted in the escalation in expenses.
The budget for the Games was increased to £9.3bn by the government in March.
Costs 'in line'
Addressing London Assembly members on Wednesday, Mr Armitt said: "To suggest that the costs have doubled from the bid book represents a grossly misleading figure for the public.
"This figure represents a 2012 outturn cost which includes inflation, VAT, legacy conversion and earthworks.
"The bid figure was a 2004 figure which all the bidding cities were asked to give. Insofar as a comparison can be made with the bid book the figures are broadly in line," he said.
The designs for the 80,000-seat stadium will be unveiled later this month, he said.
After the Games the stadium will be scaled down to accommodate 25,000 people.
He went on to add that the final cost of building the 20,000-seat aquatic centre, which will include a wave-shaped roof, is still not clear.
"I'm not sure where we are going to finish up... the important thing is that it does the job that is required."
The bidding document said the aquatic centre would cost £75m to construct.