The ONMS said in a statement that in cases of racism the referee should alert the fourth official who should in turn report the incident to the public security department responsible for policing at games.
"The director of the public order service has the sole responsibility for suspending the match," said the statement following a meeting with officials from the Italian football federation.
"The director, in the presence of expressions of racism or intolerance, will decide in all cases on the non-continuation of the match or its suspension on a temporary basis to allow warnings to be issued to supporters over the public address system."
Italian football federation president Giancarlo Abete had previously agreed that matches could be abandoned in cases of racism.
Last week AC Milan walked off the pitch during a friendly against lower tier side Pro Patria after Kevin-Prince Boateng refused to play on following racist abuse from a small number of supporters in the crowd.
FIFA president Sepp Blatter on Monday praised Boateng's stance as courageous but said that such gestures would not provide a long-term solution to the problem.
It was also announced that security forces would hold regular exercises "to test the flow of information, the effectiveness of emergency plans, as well as knowledge of procedures by the stewards and policing officials."
But the ONMS, a department of the interior ministry, added that the problem was caused by a small minority while violence at Italian matches was also on the decline.
"There has been a further drop in the number of violent incidents, while manifestations of racism and intolerance sporadic and always limited to a restricted group," it said.