Nigeria has confirmed two new cases of Ebola, bringing the total number of infections in Africa’s most populous country to nine, including two deaths.

“We have an additional two confirmed cases. So the total now, we have nine confirmed cases (including two deaths). The same two we told you about: the index case and the health worker,” Health Minister Onyebuchi Chukwu told journalists.

Earlier on Friday, President Goodluck Jonathan declared a national emergency over the deadly virus.

During a visit to Lagos, Chukwu said Nigeria had six suspected cases that were under investigation and 139 people had been placed under surveillance.

“As we talk, we do have six suspected cases currently under investigation … Now altogether, all those we have placed under surveillance stand at 139,” he said.

An American-Liberian, who flew into the country from Monrovia, and a Nigerian nurse are the two people who have died of Ebola virus in Lagos in the past two weeks.

The minister said the government had approved life insurance policy for all those taking care of Ebola virus patients and involved in contact-tracing.

The president earlier called on the population to avoid large gatherings in order to prevent the spread of the virus.

“Religious and political groups, spiritual healing centres, families, associations and other bodies should … discourage gatherings and activities that may unwittingly promote close contact with infected persons or place others at risk,” said a statement issued by the president.

Jonathan also approved the immediate release of 1.9 billion naira ($A12.55 million) to fund measures against the spread of the virus.

Measures to be taken include the setting up of additional isolation centres, screening at borders and contact-tracing.

In addition, the president warned against any movement of corpses to other parts of the country as well as spreading false information about the virus.

World Health Organisation chief Margaret Chan said in Geneva on Friday the epidemic in west Africa, which has killed nearly 1000 people in Guinea, Liberia, Sierra Leone and Nigeria, was the worst of its kind in four decades.