Giuseppe Procaccini quit following allegations that he met with Kazakhstan’s ambassador in Rome ahead of the forced removal of Alma Shalabayeva and her six-year-old daughter at the end of May.
Speaking in parliament last week, Prime Minister Enrico Letta called for a full investigation into the incident. Shalabayeva, who is married to dissident Mukhtar Ablyazov, was deported back to Kazakhstan on the grounds that she had false documents.
The decision has been reversed since Letta’s intervention, although it is unclear whether Shalabayeva and her daughter will be allowed to leave Kazakhstan.
Procaccini’s resignation piles pressure on Interior Minister Angelino Alfano, a member of the People of Freedom (PdL) party and ally of the former prime minister Silvio Berlusconi.
On Tuesday,a police report into the incident was given to Alfano which details the circumstances leading up to the deportation, Corriere della Sera reported.
A vote of no confidence against the interior minister is due to be discussed in the Senate on Friday. The vote was put forward by the Five Star Movement (M5S) and the Left Ecology Party (SEL), Corriere said.