Two separate confrontations were reported southwest of the Tamil Tiger political capital of Kilinochchi on Friday and sporadic fighting continued afterward, the ministry said.
"Heavy fighting at the Akkarayankulam and Iranamadu areas has been reported between troops and LTTE since Friday morning," the ministry said.
It gave no details of casualties and said the authorities had decided not to release figures of those killed and wounded in the latest round of fighting.
The ministry said earlier this week it would not divulge details about casualties because of the "need for operational security."
The announcement came just after the military reported 36 soldiers were killed in the worst single loss for security forces in the past six months.
There was no immediate word from the Tigers about the latest fighting, but the guerrillas in a statement said military shelling had killed two civilians south of Kilinochchi.
Defence ministry maps show troops are about 10 to 15 k