More than 92 per cent of Liberal Democrat MPs agreed that charities were better at campaigning than companies. Some 77 per cent of Conservatives and 76 per cent of Labour MPs questioned said the same.
But charities were advised to be more targeted in their comms to MPs.
'MPs dislike unselective scatter-gun tactics that waste resources,' said nfpSynergy researcher Gemma Tracey.
nfpSynergy's latest Charity Parliamentary Monitor surveyed a representative sample of 160 MPs.