The latest budget report revealed that the saving of £20m to the Olympic Delivery Authority (ODA) programme confirmed in the recent spending review had been achieved.
Efficiency savings and a decision to remove a 'wrap' from the Olympic Stadium has helped drive down the AFC, which now stands at £7.232bn - compared with £7.261bn in June.
According to the London 2012 Olympic and Paralympic Games Quarterly Economic Report, the overall public sector contribution to the event remains at nearly £9.3bn.
Hugh Robertson, minister for sport and the Olympics, said: "The ODA has continued to drive down costs and deliver savings despite this being the most complex year in construction terms.
"The saving of £20m identified in the spending review has been achieved with little material impact to the programme."
ODA chief executive David Higgins added: "We have made savings as part of the spending review process without jeopardising successful delivery and in total have now saved over £750m since the start of the project to keep us on track."
As part of the spending review settlement, around £0.5bn is to be made available as contingency for "cross-programme issues", while £1,143m of contingency remains available.
