Dal Babu, ex-president of the National Black Police Association, said the Independent Police Complaints Commission had “flipped” too far and did not look into racism claims fairly.
He spoke days after a misconduct case of three officers accused of racism against a black firefighter collapsed.
The IPCC has rejected Mr Babu’s claims.
Mr Babu, a former Metropolitan Police chief superintendent who retired three years ago, told BBC Radio 4’s Broadcasting House programme the IPCC had been “incredibly unfair against white officers”.
He said racism was rife in the police when he joined in the 1980s, but he was now worried the IPCC had “flipped and is more likely to believe black complainants than white police officers”.
Mr Babu said he had a “long history of fighting for equality in the police service” and wanted officers to be held to account, but said it must be done fairly.