Police chiefs in the North have suspended four police officers from duty after the discovery of racist and sectarian text messages.
"We expect our staff to behave ethically and with the utmost integrity at all times both on and off duty," the PSNI said in a statement.
"Any officer who fails to abide by the high standards of behavior expected of all officers as laid out in our code of ethics can expect to be rigorously investigated."
Since the Good Friday Agreement, recruitment in the PSNI has increased Catholic representation in the force to 29.76pc Catholic. In 2001, the force it replaced -- the RUC -- was 8.3pc Catholic.
Meanwhile in England, London's Metropolitan Police, Britain's largest police force, said it was dealing with 10 new race-related complaints involving 20 staff, among them an allegation that an officer used a racial slur while arresting a black man in the aftermath of England's riots last August.
Deputy Commissioner Craig Mackey said a total of eight officers have been suspended while the cases are investigated by the country's police standards watchdog. London police have long attempted to tackle allegations of racism.
A major report commissioned in the wake of the 1993 death of a black teenager concluded that Scotland Yard was "institutionally racist".
The report said that the force had had failed to properly investigate the killing because of its hostility to London's black community.