Voluntary sector think-tank nfpSynergy surveyed 150 MPs and 100 peers for its Charity Parliamentary Monitor.
It found that 54 per cent of MPs said the most influential lobbying technique was holding face-to-face meetings with them at Westminster. But only 16 per cent said this was frequently used.
The next three most influential methods were constituency-based, with constituency correspondence (39 per cent), constituency events (37 per cent) and constituency business (36 per cent).
But only 14 per cent of MPs said constituency business was being frequently used and only nine per cent said the same for constituency events.
The research also questioned the wisdom of charities sending delegations to party conferences. Just 13 per cent of MPs and nine per cent of peers said this was the best way for charities to influence them.