The firm, a subsidiary of Malaysia Telekom said lower roaming revenues as well as service disruptions in the northern and eastern areas of the island affected mobile performance.
Dialog is expecting better performance in eastern Sri Lanka after the government cleared most of the area.
It said 15.54 billion raised from a rights issue will boosts infrastructure and subscribers and also cut interest costs in the future, the company said.
In the past year Dialog had added one million new users taking the subscriber base to 3.66 million by June 30. The prepaid segment had increased 50 per cent from 2.09 million to 3.14 million while post paid