Some people are being approached at the roadside or in hospital to encourage them to make a compensation claim, it was found.
A survey of 2000 adults involved in a crash in the past three years, by insurance firm LV=, revealed one in four would not have made a claim if they had not been pressured.
One in 20 said they were contacted within two hours of an accident, sometimes while they were receiving medical attention, while one in five said they were encouraged to make a claim by a police officer.
A number of police forces share accident victims' details in exchange for a fee, said the report.
John O'Roarke, managing director of LV= car insurance, said: "The heavy-handed tactics of the claims farming industry has resulted in record levels of compensation claims for whiplash and other personal injuries, despite falling accident rates.
"Crash victims are being aggressively targeted by those who can make money out of their details and they are literally hounding them to make a claim within moments of an accident."