The impacts of the Sudan crisis are unfurling along multiple fronts in South Sudan, Nicholas Haysom, the top UN envoy in South Sudan, said on Tuesday.

Since mid-April when the conflict erupted in Sudan, over 117,000 people have crossed over to South Sudan from Sudan, 93 percent of them are South Sudanese returnees, he told a UN Security Council briefing.

South Sudan's absorption capacity is under strain, and the economic impact of the conflict has cast a shadow on an already fragile situation in the country, said Haysom, the UN secretary-general's special representative and head of the UN mission in South Sudan.

The sudden interruption of imports from Sudan has resulted in essential commodities being "out of reach" for the ordinary people in South Sudan, he said.

On the political side, the conflict in Sudan reduces the much-needed bandwidth, both domestic and international, to focus attention on South Sudan, which is in its critical phase of transition, warned the envoy.

"Now is not the time to take our eyes off the ball in South Sudan. What we can learn from Sudan is how quickly hard-won peace gains can unravel," Haysom said.

He noted that the crisis in Sudan has implications for the implementation of the revitalized peace agreement in South Sudan.

"As it stands today, South Sudan is not ready to roll out an electoral process," Haysom said, adding that all stakeholders recognize the urgent need to address the issue. "We also believe that with a united effort amongst all parties, it may be possible for South Sudan to make up the gap."

He expressed the hope that with cooperation, partnership and sustained leadership, "a positive change in the lives of the South Sudanese people can be achieved."