South Sudan's government launched a new round of peace talks with rebel groups on Thursday in Nairobi, with Kenya mediating after earlier negotiations fell apart in 2022.

Previously, talks between the government and a coalition of rebel groups -- which did not sign a 2018 peace agreement that ended a five-year civil war -- were brokered in Rome by a Catholic association with ties to the Vatican.

But the government withdrew from the negotiations in November 2022, accusing the rebels of using the talks "to buy time as they prepare for war."

The Rome-based Community of Sant'Egidio, a Catholic association that has been working to restore stability to violence-wracked South Sudan, adjourned the talks in March last year.

Following a request from President Salva Kiir, Kenya agreed to step in as mediator, appointing former army commander Lazarus Sumbeiywo to lead the talks.

Sumbeiywo previously mediated a 2005 peace deal between Khartoum and South Sudanese rebels, paving the way for South Sudan's independence from Sudan six years later.

The world's newest nation has suffered from chronic instability since winning independence, including a civil war that killed nearly 400,000 people between 2013 and 2018.

As the talks were officially launched, Pagan Amum, leader of Real-SPLM (Real-Sudan People's Liberation Movement), spoke on behalf of the rebel coalition, the Non-Signatory South Sudan Opposition Group (NSSOG).

"South Sudan is threatened with disintegration and collapse into chaos and disorder. It is gripped by multiple crises," he warned.

"We are the founding mothers and fathers of this new nation, our historical task is to lay the foundation of this new nation... To achieve that, we have to... overcome that hatred that has filled our hearts," he said.

"I believe this is our last opportunity and we must take this seriously and engage in dialogue."

The groups represented in the negotiations include the South Sudan United Front, Real-SPLM, South Sudan People's Movement and the National Salvation Front-Revolutionary Command Council, a splinter faction of the National Salvation Front which has refused to join the talks.

Kiir told an audience that included Kenyan President William Ruto that his government was ready to negotiate "in good faith and with an open mind", saying he hoped the rebels had "similar convictions and a similar desire for peace".

Negotiations between Juba and the rebel groups began in 2019 but have failed to curb violence in the south of the country, despite a ceasefire signed in January 2020.

One of the world's poorest nations despite oil resources, South Sudan has endured natural disasters and an economic crisis, with political infighting fuelling further violence.

Some nine million people are in need of humanitarian assistance, according to the UN.

The crisis is compounded by the return of hundreds of thousands of South Sudanese refugees fleeing Sudan's brutal war.