The Olympic Delivery Authority has announced 88% of the building programme for London 2012 is now complete.
It has also been announced the anticipated final cost of the project fell by £16m during the last quarter.
This has prompted Sports Minister Hugh Robertson to say for the first time he is "confident" the project will come in under its £9.3bn budget.
He said: "With one year to go construction is 88% complete, ahead of time and under budget."
Mr Robertson said the Olympic Delivery Authority (ODA) and their contractors had done a "remarkable job to deliver top quality facilities in a challenging environment imposed by a fixed deadline and strict budget".
He said: "They have continued to drive down costs which means we can celebrate one year to go with confidence and a real sense of excitement and expectation."
The anticipated final cost is now £7.25bn, down £16m since May.
Five venues, the latest of which is the International Broadcast Centre, are now complete and the Aquatic Centre will soon be completed and unveiled.
Last month work on the Olympic station in Stratford, east London, was also completed.
More than £125m has been spent on upgrading the station which will handle half of all spectators travelling to the Olympic Park.
Capacity at Stratford has been trebled to accommodate 120,000 people during peak hours in 2012.
Work began earlier this month on a £50m cable car project to link two Olympic venues on opposite sides of the River Thames.
Two new stations will be built in the Royal Victoria Dock and on the Greenwich Peninsula and once finished, the cable cars will run 50m (164ft) above the river carrying up to 2,500 people an hour.
It will connect the O2 arena in North Greenwich to the Excel exhibition centre at the Royal Victoria Dock.