Colombia Red Cross rescue chief, Cesar Uruena, said the Italians had not yet contacted their families following the disaster.
The Italian foreign ministry's crisis unit is working to establish the fate of the citizens.
The landslide devastated the area of Mocoa at the weekend, killing more than 250 people and injuring hundreds.
Heavy rain flooded the town causing mud and debris to bury houses in the early hours of Saturday, while many residents were asleep.
The death toll currently stands at 254, while authorities have estimated that it could rise to 300.
At least 170 of the dead have been identified and rescue efforts continue under the direction of President Juan Manuel Santos, who rushed to the devastated area on Saturday following news of the disaster.
"Until we have the last person identified we are not going to stop," President Santos said.
