A cholera outbreak in Nigeria’s northeast has killed nearly 100 people over the past two weeks and infected thousands more, the United Nations said.

The number of recorded cases in Yobe and Borno states currently stands at 3,126, including 97 deaths, the UN Office for the Coordination of Humanitarian Affairs (OCHA) said on Saturday.

The outbreak was declared two weeks ago in restive Borno state, where hundreds of thousands of displaced people live in camps after fleeing the armed group Boko Haram.

On Wednesday, the UN reported more than 500 people have died from cholera in the Lake Chad region since the start of the year, representing the worst outbreak to hit the area in four years.

Expected floods and heavy rains were "an ideal environment for the outbreak to spread”, OCHA warned.

It said Nigeria was the worst-hit with 24,000 cases overall, adding immediate action was needed to stop the spread of the disease.

Waterborne diseases are a constant threat in the Lake Chad region because of a lack of adequate sanitation, as well as stagnant groundwater during the rainy season.