Nieto will be sworn in Saturday, but the Mexican Legislature is already moving forward on a bill to eliminate the Public Security Ministry, which employs 36,000 police officers, Tribune Newspapers reported Monday.
Many of those officers will lose their jobs when the ministry's responsibilities are transferred to the Interior Ministry.
During the six-year administration of outgoing president Felipe Calderon, the number of police in the Public Security Ministry grew by a factor of six as Calderon instituted a massive pushback against the violence and power of the country's well-funded drug cartels.
Despite training by the United States, the ministry's police force has been hounded by questions related to corruption, collusion with criminals, human rights abuses and even shootings of U.S. security officers.
Nieto says his plan would make security operations more efficient and improve inter-agency cooperation.
Critics say the plan would merely move operational chairs around and waste the achievements of the past six years.
They also note that the Interior Ministry was often used in the past by Nieto's PRI party for political repression.
Human rights activist Gustavo de la Rosa said Nieto's plan "goes against all logic" because the federal police have succeeded in lowering the murder rate in parts of Mexico.
However, Raul Plascencia, president of the National Human Rights Commission, said "the expected success did not occur," noting the crime rate was still high and that human rights abuses have grown.