Five officers have been suspended, The Independent reported. The charges involve the use of racial slurs and other racial targeting.
Many of the cases came to light because other police officers reported them, The Daily Telegraph said.
Commissioner Bernard Hogan-Howe urged officers this week to come forward when they see inappropriate conduct.
"I will not stand for any racism or racists," Hogan-Howe said. "We have a duty to challenge or report any behavior by colleagues which is less than the high standard demanded by the service and Londoners themselves. You cannot avoid that duty. Nor can I."
The new allegations were referred to the Independent Police Complaints Commission.