Troops smashed 16 guerrilla bunkers in the district of Mannar on Tuesday after killing at least 22 rebels, the defence ministry said.
Security forces also killed 45 rebels along the northern frontlines on Monday, the ministry said, putting its own losses at two soldiers dead and 10 wounded.
There was no immediate comment from the Liberation Tigers of Tamil Eelam (LTTE), but the pro-rebel Tamilnet.
com website said the guerrillas were using booby-trapped devices and snipers against attacking troops.
Since the beginning of January, the Sri Lankan defence ministry has claimed its forces have killed 815 rebels for the loss of just 30 soldiers.
Both sides are known to give wildly varying casualty figures which cannot be independently verified.
The government bars reporters from visiting frontline areas and rebel-held territory.
Sri Lanka pulled out of a Norwegian-brokered truce with the rebels this month, underscoring its belief that it has the upper hand in the drawn-out conflict. Ten