Both South Sudan's army and rebel groups are using weapons imported from China, Ukraine and neighbouring Sudan in fighting that has claimed dozens of civilian lives, Amnesty International said Thursday.

As well as killing or injuring dozens of people, the clashes have left houses destroyed and forced people to flee their homes, the report said.

The devastation came in fighting between the South Sudanese Armed Forces, known as the Sudan Peoples Liberation Army (SPLA), and the rebel South Sudan Liberation Army (SSLA) in 2010 and 2011, it said.

The army was using Ukrainian-supplied T-72 battle tanks, said Amnesty.

"These battle tanks are entirely unsuitable for urban fighting as they cannot distinguish between military and civilian objects in urban areas," said a statement from the group.

The rebel SSLA laid Chinese-made anti-vehicle mines and were firing Sudanese-made ammunition.

"Scores of civilians have been killed or injured in the past year due to the laying of these mines by the SSLA and this also increases food and fuel costs as the mines hamper access in the region," said Amnesty.

Amnesty International's Africa director Erwin van der Borght denounced the trade in arms there.

"Governments must immediately stop supplying South Sudan with conventional arms, which have been used to commit violations of international humanitarian and human rights law, until adequate systems of training and accountability are in place," he said.

On Monday, talks begin in New York for a new arms trade treaty (ATT).

"The ATT talks are an unprecedented opportunity to stop arms getting into the hands of human rights abusers," said van der Borght.

South Sudan seceded from Sudan on July 9 last year but has since been wracked by internal and external conflict.