Sudan expulsions of NGOs leave aid gap -UN

* U.N. chief might appeal directly to Sudanese president

* U.N. says Sudan has seized some assets

* Bashir promises no more expulsions - U.N. officials (Adds diplomats on meetings with Bashir)

UNITED NATIONS, March 9 (Reuters) - The Sudanese government is unable to take on the work of aid groups it has ordered out of the country's war-ravaged Darfur region, the top U.N. humanitarian affairs official said on Monday.

The African nation shut down 13 foreign and three local non-governmental organizations, saying they helped the International Criminal Court (ICC) in the Hague issue an arrest warrant for Sudanese President Omar Hassan al-Bashir.

U.N. humanitarian affairs chief John Holmes predicted a daunting challenge if the government in Khartoum didn't reverse its expulsion of the groups, which he said accounted for approximately half of the humanitarian aid capacity in Darfur.

"We do not, as the U.N. system, the NGOs do not, ... and the (Sudanese) government does not have the capacity to replace all the activities that have been going on, certainly not on any short- or medium-term basis," Holmes told reporters.

His remarks came several days after Sudanese U.N. Ambassador Abdalmahmoud Abdalhaleem said his government would have no problem filling in any gaps in aid distribution created by the expulsions.

Secretary-General Ban Ki-moon said last week that U.N. humanitarian operations in Darfur, where some 4.7 million people rely on aid, would face "irrevocable damage" if the decision to shut down the aid groups was not reversed.


U.N. spokeswoman Marie Okabe said Ban had not spoken with Bashir in the aftermath of the ICC announcement last week that it was charging him with crimes against humanity and war crimes stemming from the six-year conflict in Darfur.

Pro-government militias are accused of widespread atrocities in the restive region, where at least 200,000 people have been killed and some 2.7 million driven from their homes.

Holmes said the expulsions were retaliation for the ICC move and said Ban, who is on a trip to Haiti, had been attempting to resolve the crisis and might personally appeal to Bashir to permit their return.

U.N. officials told Reuters that the head of the U.N. mission in Sudan, Ashraf Qazi, spoke with Bashir over the weekend. They said the Sudanese leader had told Qazi that he would not back down over the expulsions.

But they added that the Sudanese leader had told Arab League Secretary-General Amr Moussa that no other humanitarian aid organizations would be ordered out of the country.

Holmes said that U.N. and NGO staff had faced harassment at the hands of Sudanese security forces, including "intimidatory behavior" and confiscation of vehicles, computers and other assets, and that U.N. officials had complained to Khartoum.

He added that the supply of food and water at refugee camps in Darfur would be more difficult in the coming days. (Additional reporting by Megan Davies; editing by Paul Simao)