However, it's uncertain the additional force will be able to protect the local populations or bring stability to the war-torn country. There are already 12,000 UN peacekeepers in the country.
The latest round of violence began in July with clashes among the Sudan People's Liberation Army, loyal to President Salva Kiir, and those loyal to former Vice President Riek Machar, who contends Kiir's appointment of a replacement vice president in July is illegal.
"The refugees have brought to us very disturbing reports," UNHCR Spokesman Melissa Fleming said at a briefing in Geneva.
Armed groups "are looting villages, murdering civilians, and forcibly recruiting young men and boys into their ranks," Fleming said. "We are very concerned, and are appealing for parties to move back to the peace agreement."
Despite a peace deal brokered on July 11, clashes continue.
It has been an ongoing problem since December 2013, when Kiir ousted Machar as South Sudan's first vice president and accused soldiers loyal to his rival of staging a coup.
That violence forced more than 2 million people to flee their homes, including around 200,000 civilians who went to UN bases seeking refuge from both government and opposition forces.
Reports of atrocities in February brought about UN investigations
into how peacekeepers responded to the attack on refugees under UN protection.
Machar was reinstated as vice president in February as part of a deal to end the country's civil war. But after renewed fighting at the start of July, Machar fled the country and said he was being targeted by Kiir's troops.
Last week, Kiir removed Machar again from his post, replacing him with Taban Deng Gai, who had previously served as Machar's chief negotiator, as well as the country's mining minister.