Election officials also confirmed on Sunday that the government and its allies were on track to win control over a 35-member provincial council in the east coastal region, a part of which was under rebel control before an offensive last year.
"The government victory at the eastern polls has shattered the wild dreams of the West-backed Eelamists [Tamil Tigers]," Patali Champika Ranawaka, the environment minister, said.
He said the results have proved "not only Sinhalese but even Tamils have placed their faith in the government".
The elections on Saturday are part of plans by Mahinda Rajapakse, the Sri Lankan president, to boost the war effort against the Liberation Tigers of Tamil Eelam (LTTE), who still control a swathe of jungle in the north.
The president wants to partially devolve power from his ethnic Sinhalese-dominated government to the TMVP, a party of Tamil Tiger defectors based in the east, to undermine rebel demands for a separate ethnic state.