The Directorate General of Civil Aviation (DGCA) has constituted a team to carry out the investigation, the Civil Aviation Ministry said in a statement.
The probe team is being headed by the Director of Air Safety at the DGCA, it said.
According to the Ministry, the radioactive material leak was observed at the IGI Airport after a consignment which included liquid sodium iodide and sodium molybdate arrived from Istanbul by Turkish Airlines flight TK-716 at 04:32 hours today.
Turkish firm Celebi provides ground handling facilities at the Indira Gandhi International Airport.
The affected area has been cordoned off, the statement said, adding that flight operations at the airport, however, was not affected.