"The first contingent of 250 Nigeria experts will be deployed soon," he said but did not provide a date.
Nkosazana Dlamini-Zuma, Chairperson of the African Union Commission, told reporters in the Sierra Leone capital Freetown that countries in East Africa had responded with a pledge of 600 health workers.
Democratic Republic of Congo, which has suffered six outbreaks of Ebola since the disease was first detected there in 1976, had also pledged to train 1,000 volunteers, she said.
The WHO originally appealed for 12,000 local staff and 750 foreign experts but has raised those targets to 20,000 and 1,000 respectively. WHO assistant director general Keiji Fukuda said there were now only 600 foreign experts.
AU STILL WAITING FOR RESPONSES
The WHO declared Nigeria Ebola-free on Monday but Alhassan said the outbreak remained a threat to the country until it was completely neutralised.
The international community has ramped up aid including sending some medics and supplies to Sierra Leone, Guinea and Liberia, where the epidemic has crippled poor and under-equipped health systems.
The United States is deploying a 3,000-strong military mission to build up to 17 Ebola Treatment Units (ETUs) and train local doctors, while Cuba has dispatched hundreds of medical personnel.
Alhassan said the Nigerian Centre for Disease Control would also support Sierra Leone, Liberia and Guinea in training their health workers. "What we are waiting for now is that the request has to come through (West African regional bloc) ECOWAS and has to be coordinated by WHO," he said.
Speaking in Freetown, Dlamini Zuma said the AU had felt obliged to make a direct plea to members in mid-October because it realised that appealing for volunteers to come forward individually was not enough for the scale of the crisis.
"We wrote to all our heads of state asking them to give us health workers who would be deployed here in these three countries...We are still waiting for responses," she said.
"East Africa has responded and they have pledged more than 600 health workers, DRC has also pledged about 1,000 but they will bring them in phases," she said. "They say they will start probably with about 200. So we are waiting for those to come and also pledges to come from other countries."
Congo Health Minister Felix Kabange told Reuters in mid-October the government aimed to train more than 1,000 volunteers to fight Ebola, which he hoped would inspire "African solidarity". He invited other countries to send volunteers to new training centres in the capital Kinshasa.