Campaigners have warned that schools could reduce the amount of outdoor space for pupils after the Government changed the rules.
The Department for Education confirmed a legal requirement for the specific amount of space schools must set aside for team sports has been dropped.
Secondary schools currently have to provide 38 to 50 square metres of "game playing field" for every child.
Under the new regulations, schools will simply have to provide "suitable outdoor space" for PE and for pupils to play outside.
Further non-binding guidance will be consulted on and published next year.
Sources close to the Education Secretary Michael Gove told Sky News the aim was to reduce bureaucracy and give schools the flexibility they need.
They denied the changes would lead to playing fields being sold off.
But campaigners have accused the Government of putting the Olympic legacy at risk by weakening the rules.
The Fields in Trust charity warned that playing fields could be cut by 15% because of the plans.
And Tim Lamb, the chief executive of the Sport and Recreation Alliance , said: "Without a minimum requirement, the danger is that short-term expediency could jeopardise the ability of schools to deliver sport for future generations."
The news comes after David Cameron vowed to put competitive sports such as netball and football into the national curriculum for primary schools.
A Department for Education spokesman said: "These regulations set out for the first time that all schools must have access to suitable outdoor space for both formal PE lessons and for outdoor play.
"By removing pages and pages of bureaucratic restrictions we will make it easier and cheaper to provide the extra school places that this country needs so urgently.
"Our extremely strict rules on playing fields will stay firmly in place. This Government has only approved sales if the school has closed, has merged or if equal or better facilities are being put in their place.
"We will be consulting later this year on how the new guidelines should be implemented."
The Government is already under fire for allowing the sell-off of more than 20 school playing fields - despite a promise in the coalition agreement that they would be protected.
It has also been criticised for dropping a target for state schools to provide at least two hours of PE a week.
And in 2010 Michael Gove attracted criticism for axeing the £162m School Sports Partnerships.