The South Sudan government wants the Inter-Governmental Authority on Development (Igad) and Troika member states to exclude former army boss Paul Malong from the upcoming peace talks.
The Presidential Press Secretary, Ateny Wek Ateny, in a press briefing on Tuesday in Juba, said Gen Malong's participation would affect the peace process, adding that the former military commander believed in violence more than peace.
Gen Malong formed his rebel movement on Monday and declared that he was ready to oust President Salva Kiir to steer democracy in the young nation.
He also expressed interest in taking part in the upcoming Igad peace talks.
But Mr Ateny said Gen Malong was already blacklisted by the international community for being corrupt and a master of impunity during his military service from 2014 to May 2017.
He said the key reason why the controversial former army commander should be excluded is his interest in violence.
"The Americans sanctioned him for being the most corrupt and the breeder of impunity," he said.
"First of all, Malong was sanctioned by the same international community for the role they thought he played as part of the government when he was the Chief of General Staff of the army," he added.
He said the former army boss was also to blame for the breakdown of the 2015 peace agreement that forced Dr Riek Machar out of the country in 2016.
"Malong was against the peace agreement on the resolution of the conflict in South Sudan. That is why he staged almost three attempted coups against President Kiir between 2015 and 2016.
"At some point he wanted the president sent home to Warrap so that he (Malong) takes over but his plan was foiled, simply because of intelligence," Mr Ateny said.
Mr Ateny added that Gen Malong was responsible for the breakdown of rule of law in South Sudan, saying that he misused his powers as army Chief to breed impunity.
"It is unfortunate Malong is talking about impunity and democracy. He is advocating for something he never knew before," he said.
"During his time in office as army Chief of Staff, banks were opened at night for General Malong to take money and he squandered a lot of money that time."