Security forces carried out simultaneous attacks against Tamil Tiger strong-points near the town of Kilinochchi, and also on the Jaffna peninsula, military spokesman Udaya Nanayakkara said.
In a rare statement announcing casualty figures, he said that another 160 government soldiers and an estimated 250 rebels were wounded.
The military said 10 of its soldiers were also missing after Tuesday's fighting.
The defence ministry decided in October to stop revealing daily casualty figures, saying they would affect military operations.
Nanayakkara said troops were consolidating positions they had captured from the Tigers, who have offered stiff resistance to government forces advancing on Kilinochchi, 330 kilometres (210 miles) north of Colombo.
The defence ministry said Mi-24 helicopter gunships were deployed to destroy a Tamil Tiger boat which had been attacking troops operating in a coastal area in the northern mainland on Tuesday.
There was no immediate comment from t