Agadez, the main city in central Niger, has become a revolving door for economic migrants seeking to reach Europe via Libya, winning notoriety as Africa's people-smuggling capital.
"We are going to Niger following a request by the government at the start of December to... reinforce the security measures in the territory and at the borders and to support the police force," he said.
He said Niger was "the main transit country" in Africa for Europe-bound migrants, adding that it was also "perhaps the most willing to cooperate in this matter as it is a transit country," and does not receive remittances from migrants settled abroad.
The soldiers being sent to Niger have mainly served in Iraq and Kuwait.
A first contingent of less than 200 is expected to leave early next year.
The troops will have two planes and 130 vehicles at their disposal, according to Italian media.