The second round of peace talks on South Sudan, scheduled to start later Monday, has been postponed, officials said.

"The talks are not resuming today," South Sudan government spokesman Michael Makuei told AFP. A government official from host country Ethiopia confirmed the postponement.

Makuei said the second round would start on Tuesday afternoon, but there was no immediate confirmation.

"We are informed that his excellency the prime minister of Ethiopia wants to attend the opening session. We are told that it is tomorrow afternoon," Makuei said.

The first round of talks last month resulted in the South Sudan government side and rebels led by former vice president Riek Machar signing a ceasefire agreement, but fighting has continued in the vast and impoverished country.

The second round of talks will be trickier as it is supposed to bring about a comprehensive and durable solution to South Sudan's problems.