Many US charities will only take on volunteers who have insurance, including fundraisers, after an avalanche of personal injury claims by volunteers created a perception that the sector was a soft touch.
George Cook, chief executive of Charity Logistics said: "At the moment, charities are like the passengers on the Titanic taking an 'it will never happen to us' view. But under the water, hidden from view is something which is going to tear through their hulls."
Cook recently returned from a fact-finding mission to the US where the Government has set up a Non-profit Risk Management Center to tackle the problem. Charity Logistics is now proposing a consultation day on 1 March to discuss the risk posed by litigious volunteers, and plans to follow this up with a conference in June.
In the US, it is also becoming more common for charities to draw up agreements with volunteers to avoid being taken to employment tribunals.
Cook added: "Figures show that people are more likely to take voluntary sector organisations to court than private companies because they think the latter will be tougher and they'll lose.
There is an expectation that charities will settle out of court to avoid bad publicity.
"It's only a matter of time before UK charities are hit by a myriad of claims. There are tens of millions of pounds involved. It is vital that we stop these hard-earned public donations being paid out on avoidable mistakes or malicious claims."