Violence in the country has increased in recent months as political infighting threatens a fragile 2018 peace deal.
The latest attack took place in Abiemnhom in Ruweng, when youth from Mayom County in neighbouring Unity State stormed the town and fought for more than three hours, Information Minister James Monyluak Majok said on Monday.
Ninety of those killed are believed to be civilians, and 79 government soldiers. The death toll could rise further, Monyluak added.
"We think this number may rise because when the attacks happened many people ran to the bush, and we still have some people who are missing," Monyluak told Reuters.
He added the government did not know the intention behind the attack.
The information minister of Unity State, Nyakenya Johannes Keah, did not immediately respond to a request for comment.
The violence highlights concerns, including from the United Nations, of deepening instability since the arrest of former first vice president Riek Machar a year ago.
President Salva Kiir signed a peace agreement with Machar in 2018 to end five years of civil war that left an estimated 400,000 dead.
But implementation of the deal has been slow and the opposing forces have clashed frequently over disagreements about how to share power.
