A CIVILIAN Zimbabwean peacekeeper held for more than 100 days by kidnappers in Sudan’s Darfur region has been freed, United Nations officials said.

Gunmen abducted the Zimbabwean along with a Nigerian man from Darfur's joint U.N./African Union peacekeeping mission in the west Darfur town of Zalingei in August, in one of a new wave of kidnappings.

"They have been released ... This is the end of a long nightmare," said Noureddine Mezni, spokesman for the UNAMID peacekeepers. "They are in good shape. We are very happy to have them back."

The Zimbabwean, who has not been named, is described as a “child welfare officer”.

The two were abducted at gunpoint from their accommodation in West Darfur state on August 29, and had been detained for 107 days before their release on Sunday.

U.N. Secretary General Ban Ki-moon took the unusual step of phoning Sudanese President Omar Hassan al-Bashir this month to ask him to step up efforts to free the two peacekeepers.

It was not clear what the kidnappers had been demanding as the price of the hostages' freedom.

A spokesman for Sudan's Foreign Ministry, Moawia Osman Khalid, told Reuters negotiations with the kidnappers had been carried out via local elders.

There have been reports that both fell ill during their captivity, although UNAMID officers said there was a chance the kidnappers were making up the reports to step up pressure.

African Union (AU) Commission President Jean Ping has said he is "deeply gratified" to learn about the release of two peacekeepers.

"The Chairperson welcomes this positive development in ensuring the safety and the security of all humanitarian and peacekeeping personnel working in Sudan and looks forward to enhance cooperation with the government of Sudan in this area," Ping said Sunday.

Gunmen have abducted at least 14 foreigners in Darfur and just over its border in neighbouring Chad and the Central African Republic since March.

Aid workers say they have had to take extra security precautions and scale down work in remote areas to protect their staff.

A counter-insurgency campaign against rebels who took up arms in Darfur in 2003 drove more than 2 million people from their homes and created a humanitarian crisis, which the United Nations says has claimed 300,000 lives.