"We are already in the North and will be adding 170 new towers in the North and East by end April," Dumindra Ratnayaka, chief executive officer of Etisalat said.
"Right now we are having a bit of an issue with the weather but we are on target."
A 30-year war with Tamil Tiger separatists ended in May 2009, allowing infrastructure to be rolled out.
The company already has 1,100 base stations island-wide and last year started a 163 million US dollar program to boost base stations to above 1,500 and add broadband capacity.
"We are rolling out 450 new towers island-wide with third generation (3G) very soon," Ratnayake said.
The firm had added about a million subscribers in the past year.
"We have more than a 3.5 million subscribers and are growing.
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Sri Lanka's 15 million subscriber market is shared between Dialog Axiata, Sri Lanka Telecom Mobitel, Airtel, Hutch and Etisalat.