Franco-British former hostage Gauthier Lefevre on Saturday described the "daily struggle" of staying positive for five months as the kidnap victim of a criminal gang in Sudan's war-torn Darfur.

"Staying positive for the whole day was a daily struggle," the International Committee of the Red Cross (ICRC) worker told reporters in the Sudanese capital two days after his release.

Lefevre, 35, has the unenviable record of spending the longest time in captivity of any hostage in the region -- 147 days -- since a wave of kidnappings of foreign aid workers erupted 12 months ago.

The abductions came after the International Criminal Court issued an arrest warrant for Sudanese President Omar al-Beshir for alleged crimes against humanity and war crimes in Darfur.

Lefevre was in a convoy of two vehicles clearly marked with the ICRC logo when he was seized by gunmen near the Chadian border last October 22.

His days as a hostage passed very slowly.

"Focusing on passing just that day was very important," Lefevre said.

"Not thinking ahead too much, not trying to guess the conditions of release, what was going on behind the scenes, understanding two words of Arabic and thinking does that mean next week I'll be released?"

He recalled the day half a dozen gunmen forced the convoy to stop.

"I reckoned very quickly that my nationality was not very important for them. In the car they asked me what was my nationality was, I said I was half French, half British. They were not particularly excited," Lefevre said.

It was pretty clear they were just after money, he said. Later, his abductors did indeed demand a ransom for Lefevre, but no cash was ever handed over, the ICRC's Sudan spokesman, Saleh Dabbakeh, said on Thursday.

"Most of them try to reassure me, saying "mafi mushkilet" -- no problems -- "goroush baz" -- just money ... But I also felt they never intended to hurt me or hit me or anything," Lefevre said.

"Generally I was not mistreated in any way.

"Food availability, water availability, and conditions varied but generally were okay. Very quickly I understood, at least I felt that they did not intend to mistreat me and they did not intend to hurt me. So that was quite reassuring.

"Throughout the next five months we moved camps a little bit between several areas. Every 15 days or every month or so we would move camps."

His kidnappers took Lefevre to the Kebkabiyya region, a stronghold of Darfur Arab tribes, Ahmed Tayeb Abu Gurun, head of West Darfur security told reporters on Thursday.

On Saturday, Lefevre recalled how he passed the time, guarded by two gunmen.

"There is 13 hours of daylight ... So you do spend a lot of time sitting on a dirty blanket and not having much to do and wondering about what is going on, when you will be released, what will happen," he said.

"You feel the time stops and it is difficult to remind yourself that of course the ICRC colleagues and lot of people are involved in trying to secure my release.

"And that my family and my wife are thinking of me and hoping for my release. It is sometimes difficult to keep that in mind."

Lefevre added that he was able to call his wife and the ICRC office "a couple of times."

"It was very important. Those were the highlights, and that gave me a lot of strength to remind me that the world had not forgotten about me outside."

He told how he also spent part of his time stuck in the desert by sailing the Pacific -- in his mind.

"They left me one of my books which I read several times in the first month. It was a book on the voyages of La Perouse exploring the Pacific Ocean in the late 18th century. It's a great book."

Lefevre did not know that other foreigners kidnapped since he was abducted had already been released. But he knew that two GOAL aid agency workers seized last July spent 107 days as captives. They were freed before he was taken.

"It all happened very suddenly," he said of his own release.

"On Wednesday night, a couple of people from national security turned up at my camp. I was left alone for the night. Around the evening these two agents turned up and said 'let's go.'

"So I got my stuff together and we walked off. We walked about three hours. A car was waiting for us and then we drove through the night and we got to the helicopter that took us to (West Darfur's capital) El-Geneina in the early morning.

"There was no violence at all."

A free man once again, Lefevre now plans to return to Paris before flying on to his wife's native Australia.