Italian police suspect doctors have been promoting baby milk formula over breastfeeding in exchange for kickbacks.

Italian police have placed 12 doctors under house arrest on suspicion of promoting baby milk formula over breastfeeding in exchange for kickbacks including luxury holidays.

The doctors had been bribed by several companies to prescribe baby formula for rewards worth thousands of euros, including iPhones, televisions, cruises and trips to the United States, India and Paris, the police said.

Five sales representatives were also placed under house arrest.

Health Minister Beatrice Lorenzin said there were "no adjectives to describe the seriousness of the sort of behaviour" revealed by the year-long investigation.

It was difficult to believe pediatricians had gone "against the ethics of their profession, against unanimous scientific opinions and against the indications of the health ministry in convincing mothers to use powdered milk formula in place of mother's milk," she said.

Among those in handcuffs were two chief hospital pediatricians, the police said.

AAP.