"In consideration of the improved security situation in the region it has been decided to completely lift the curfew in Jaffna. It will not be reimposed", Brigadier Udaya Nanayakkara, the military spokesman told reporters.
Jaffnaites were subject to curfew from midnight local time to 4 a.m (1830 to 2230 GMT) daily for decades due to the separatist rebellion by the Liberation Tigers of Tamil Eelam (LTTE) rebels.
Since the end of the war with rebels in May, the security situation in the north had improved, defense authorities say.
Jaffna, the cultural capital of the Tamil minority, fell into government control in 1995 after years of rebel control.