A cholera outbreak has killed 12 people and may have infected at least 134 others in the northeast Nigerian state of Adamawa, a medical official said on Wednesday.

"So far 12 people have died from the disease and there are many more cases", said Ezra Sakawa, medical director of the general hospital for Mubi, the town where the disease has struck.

"We have little manpower to deal with an outbreak of such magnitude," Sakawa said, adding that nurses were on strike.

Northeast Nigeria is ground zero for Nigeria's nine-year war against Islamist insurgency Boko Haram and its offshoot, now Islamic State's West Africa ally.

The conflict has spawned one of the world's largest humanitarian crises, with millions of people displaced and in need of aid to survive.

Those conditions are ripe for any outbreak of disease, such as cholera, to be deadly on a wide scale, humanitarian workers say.

Mubi, although less affected by the humanitarian crisis, has been attacked repeatedly by suspected Boko Haram militants, killing scores of people.