A wide range of voluntary groups, including The Christian Institute, have written to the Government saying the lobbying Bill could undermine democracy.
The Bill introduces draconian new rules to control how not-for-profit organisations speak out on issues in the 365 days before a general election.
Over 40 voluntary groups from many different backgrounds signed the letter, urging the Government to stop, listen and find a solution.
And full-page ads have appeared in three national newspapers today calling for change.
The groups, which also include Oxfam, the RSPB and Tearfund, comment: “There is a lot on which we may not see eye to eye, but we are united in concern over this Bill which could do so much to undermine democratic participation in this country.”
And they warn: “Our legal advice is that this Bill would have a chilling effect on the ability of charities and other groups to speak out about issues on which we take a stand.
“Its provisions could have prevented historic campaigns – such as those to ban land mines, remove lead from petrol and to give women the right to equal pay – from taking place at all.”
The letter comes ahead of the Bill being debated in the House of Lords today and is addressed to Lord Wallace of Saltaire – the Minister responsible for the Bill in the Lords.
The letter adds: “These measures in the Bill were drafted in haste with no consultation.
“It has had a rocky ride through the Commons, and you and your fellow Peers will no doubt be debating tough questions in the House of Lords.
“We urge you to stop, to listen, and to work with us to find a solution that will protect both the integrity of elections and the vibrancy and diversity of our democracy.”
Last week members of the House of Lords also criticised the Bill saying the Government’s handling of it so far was “a matter of significant concern”.
Baroness Jay of Paddington, the chairman of the House of Lords Constitution Committee, said: “We are critical of the hurried way in which this legislation has proceeded, which has resulted in a lack of consultation.”