The ruling UNF said on Tuesday that it had won the parliamentary elections, defeating former president Mahinda Rajapaksa's United People's Freedom Alliance (UPFA).
United National Front's John Amaratunga told Xinhua on Tuesday that the United National Party would now decide the new government after its leader Ranil Wickremesinghe was sworn in.
"We are happy with our victory. We will now form a new government after Wickremesinge is sworn in as the prime minister by the president," he said.
The UNF secured 105 seats in 22 districts of the island nation, and with the national list slot of 20 seats, it will comfortably hold 115 seats in the 225-member parliament. The UPFA obtained just over 90 seats.
Wickremesinghe had pledged to form a national government with the UPFA and minority parties.
The official results are expected to be released later on Tuesday.
