London 2012 chiefs have admitted the completion dates for the two main Olympics venues have been pushed back - but insisted the change will not affect any test events for the Games.

The Olympic Delivery Authority (ODA) have confirmed the construction periods agreed with the main contractors on both the Olympic Stadium and Aquatics Centre are longer than was predicted in November.

The body insist, however, both venues will still be ready in time for the first important deadline - the test events in the summer of 2011. "We have always said that the main Games venues would be ready by summer 2011 to allow a full year of test events before the London 2012 Opening Ceremony," David Higgins, the ODA chief executive, said. "That is the timetable that matters and nothing has changed.

"We will allow early access for LOCOG (London Organising Committee of the Olympic Games) to fit out the venues to Games-time specifications and we are on track to deliver."

The Commons' public accounts committee yesterday drew attention to the change of completion dates in their latest report. They also noted the ODA have not yet reached agreement with Lend Lease, the developer, on building the Olympic Village.

An interim deal has allowed construction work on the village to begin and ODA sources say they are confident the final contract will be agreed before the end of the year.