The decision follows after regular coach Conor O’Shea has stepped down from the role despite having a contract until summer next year after the Azzurri managed just nine wins from 40 games.
Smith, who has played nine Tests for the Springboks between 1996 and 1999 has worked with Free State Cheetahs, Super Rugby side Cheetahs and Treviso in the past.
The 47-year-old also was the assistant coach of South Africa in 2017 when Allister Coetzee was in charge of the side.
The Italian Rugby Federation has also confirmed that a permanent coach will be appointed by July next year.
“The Federation will continue the process of defining the staff of the national team for the four-year period 2020-23, which will be in office starting from July 1, 2020 in view of the summer tour in the Americas,” read a statement from the Italy board.
Italy will kick-start their Six Nations 2020 campaign with a clash against Wales at Principality Stadium in Cardiff on 1st February.