"As of today, we have recorded 5,323 cases with 333 deaths in 22 states," minister Babatunde Osotimehin said in a statement.

The first case of meningitis was reported to the health ministry in December 2008, he said. The oil-producing nation has a population of about 146 million people in 36 states.

Meningitis is the inflammation of the tissue surrounding the brain and spinal cord, and can be caused by viral or bacterial infections.

Idrissa Machinama, health commissioner of Nigeria's northeastern state of Yobe, said on Tuesday half of the state's population of 3 million people were susceptible to an attack of cerebrospinal meningitis. The state has reported 26 deaths and 240 cases.

The World Health Organisation last week confirmed that 28 Nigerians had died from meningitis.

Outbreaks of meningitis in Nigeria are common during the dry season because of the intense heat in Africa's most populous nation.

At least 200 children died of cerebrospinal meningitis and measles in the northern Nigerian city of Kano in early 2001.

Basic healthcare is limited in rural parts of the West African country, where most people live on less than $2 a day.