DFAT has urged Australians in South Sudan to leave immediately while commercial options are available amid the ongoing deadly clashes.
At least 500 people are believed to have died since last weekend, when President Salva Kiir accused his former deputy Riek Machar of a failed coup.
The United Nations says attackers have stormed a UN base where civilians took refuge in South Sudan, killing three Indian peacekeepers.
The UN has lost contact with the base at Akobo in Jonglei state, and the fate of more than 30 ethnic Dinka civilians sheltering there is also unknown.
The United Nations says around 20,000 people are seeking refuge in two UN bases within South Sudan's capital Juba.
Skirmishes began on Sunday in Juba's outlying areas before moving to the city.
The fighting has since stretched into surrounding towns, UN humanitarian coordinator Toby Lanzer said.
"In the past 24 hours we've seen clashes erupt in other towns, in particular, a town called Bor which is the biggest town in the biggest state of South Sudan," he said.
"There is a worrying trend that the violence isn't focused in and around Juba."
Listen: Full interview with UN humanitarian coordinator Toby Lanzer
Mr Lanzer says the struggle is due to political rivalries, rather than ethnic clashes.
"It is important to understand that there are members of all of the different communities and groups here in South Sudan that are on either side of the political struggle. It is wrong to characterise this as one community against another, that's not what happening. It is a struggle of a political nature."
Mr Lanzer says the situation in Juba is stabilising, but concerns remain for other areas. The existing aid operation in South Sudan has been a logistical help.
"We do have supplies here, we've got personnel here, as long as we can reach people who need help, we'll do everything we can," he said.
