pounds 30m bill 'tip of the iceberg'.
Action Against Medical Accidents (AAMA) said most traumatised patients were unwilling to demand reparations - despite the massive payout during the last five years.
Parents of newborns, those cared for in emergency units and suffering from fractures were most likely to complain.
Liz Thomas, policy manager at the charity, said: "These figures are the tip of the iceberg. The number pursuing claims is a tiny proportion of those involved in accidents.
"People are often traumatised if there's no move to explain what happened."