Shelter says that charities have been loath to "stick their heads over the parapet" and respond to media enquiries, preferring to hide behind statements from umbrella bodies such as the Public Fundraising Regulatory Association (PFRA).
The charity is warning that an emerging gulf between charities and the media and the public over face-to-face fundraising has the potential to erupt into a wider criticism of all charitable fundraising methods.
"All fundraising costs money, and if we continue to let people believe that they are effectively being conned by face-to-face, then we're opening the way for this charge to be applied against all of our fundraising programmes," said Alan Gosschalk, director of fundraising at Shelter.
In response to recent events, the Institute of Fundraising has written a letter to its 500 members urging them to voice their support for such a campaign, run through the Institute, that will seek to improve supporters' understanding of how much it costs to raise money.
"What has happened is that charities have fallen into the trap of presenting fundraising costs as being lower than they actually are," said Lindsey Boswell, chief executive at the Institute. "To counter the fallout from this we have to try and speak in a collective voice, but the profile for such a campaign should not be a faceless institution such as ourselves or the PFRA, but the charities themselves."
Gosschalk is also calling for charities to launch a co-ordinated campaign to counter the negative stories about face-to-face fundraising - or 'chugging' - by newspapers including The Times and the Evening Standard.
"Covering our ears and hoping the issue will go away is simply not an option," he said. "Without a rigorous defence of a fundraising strategy that has brought benefit to millions of our clients' lives, there is a real danger that the whole sector will get dragged down.
"We should look at how dreadful things have got in Scotland, where public trust in charities has plummeted because of bad press and take it as a warning of what could happen here."
Gill Astarita, director of development at Action For Blind People, said that the current reluctance of charities to defend their use of face-to-face fundraising agencies sent out the wrong message.
"The sector is behaving like it's embarrassed about using professional fundraising agencies and of running street fundraising campaigns," she said. "Charities can't rely on the PFRA or anyone else to defend us, we have to do it ourselves."