Millicom has operations in Sri Lanka, Cambodia and Laos.
By the end of the March quarter the firm said it had 4.
5 million subscribers in Asia, generating a profit of 4 million US dollars to the group.
The company said Thursday it had appointed Goldman Sachs, an investment bank, as advisor to the sale.
Sri Lanka's celco market is led by Dialog Telekom, a unit of Telekom Malaysia. The other key players are Mobitel, a unit of fixed access provider Sri Lanka Telecom, and Hutchison Telecom.
In January 2009 Bharti Airtel entered the Sri Lankan market as the fifth player in the midst of a deadly price war where organic growth is difficult.
"Inorganic growth options can however be explored through a potential acquisition of Tigo operations in Sri Lanka, which is estimated to command an 18 percent market share in terms of subscribers," says Channa Amaratunga of CT Capital.
"Industry leader Dialog Telecom and number two Mobitel may also be willing to pay a price to prevent Bharti Airte