Network Rail (NR) said disruptive work on the Olympics-serving railways would be suspended from the end of June 2012 to early September.

Transport for London (TfL) said non-essential engineering upgrade work on London Underground, Docklands Light Railway and Tramlink would be suspended from July 17 2012 until the conclusion of the Paralympics on September 14.

TfL said overnight maintenance work would continue as usual during this time but there would not be any planned station or line closures.

However, NR warned of "additional and enhanced maintenance work" on the Olympic routes in the weeks and months leading up to the "work-free" period to get the track ready for increased demand.

NR operations and customer services director Robin Gisby said: "With an estimated 500,000 spectators from across the UK and overseas travelling to and from Games venues each day, NR has an important role in planning the first public transport Games.

"Our aim, as always, is to deliver our work smarter and quicker and to keep the railway open for passengers.

"Through careful planning, we've been able to create a clear window around the Olympic and Paralympic Games - yet another sign that with two years to go London is well on its way to being ready."

London Mayor Boris Johnson said: "I want London to be the best big city on earth and we look forward to welcoming the world in summer 2012.

"Alongside the Games themselves, there will be a feast of fun and festivities and while it certainly will be 'business as unusual', we want to do all we can to ensure people can get around on the Tube and trains as easily, reliably and efficiently as possible."