Editors are being asked to write to their own MPs and those in local and regional newspaper circulation areas to fight proposals that would water down the Act.
Consultation is under way on the proposals that would make it more difficult - and costly for the media, and most importantly the public, to use the Act.
The FOI Act was described by former Prime Minister Tony Blair as the ‘cornerstone of constitutional reform’.
Ever since the Act came into effect after a 20 year campaign and eight years of Labour government, politicians and authorities have tried to undermine the law that allows ordinary people to find out information that they are entitled to know.
It has also been of immense value to the media in informing the public.
Now a committee of former ministers including those who introduced the Act want to make it more difficult to use, says the Society of Editors.
Nick Turner, the new president of the Society of Editors said: "This would be a cynical and, indeed, dangerous backward step in the long fight for greater openness and transparency.
"If MPs really want to serve their constituents, they will support this campaign to maintain the tremendous work of the Campaign for Freedom of Information.
"The fact that Maurice Frankel and the Campaign are still in business a decade after the Act came into force demonstrates the need for all those who believe the public have a right to know what is done in in their name and with their money, to join this vital battle."