Shadow Home Secretary Diane Abbott said "racial bias is rife in Britain's justice system" after the Lammy Report.
The report by Labour MP David Lammy found evidence "bias" and "overt" discrimination towards black and minority ethnic (BAME) individuals in some parts of Britain's justice system.
In one area of drug offences, BAME offenders were found to be 240% more likely to be imprisoned than white culprits.
Abbott responded to the report by tweeting "Racial bias is rife in Britain's justice system.The Govt must take immediate action and implement the recommendations from the Lammy Review."
Labour leader Jeremy Corbyn, a prolific tweeter on such issues, has yet to send his own message in reaction to the report.
The Government has said it will "look carefully" at the suggestions made by Lammy, whose report contains a total of 35 recommendations, including the delay or abandonment of some prosecutions.