The United Nations will this week appeal for $910-million to help tackle a humanitarian crisis in northeastern Nigeria, which has been in the grip of an Islamist insurgency since 2009 and was hit by flooding last year, documents showed on Wednesday.

The UN documents seen by Reuters showed that 7.8-million people need help in the three northeastern states of Adamawa, Borno and Yobe, and the UN aims to help 3.6-million of them.

At $910-million, it is the most expensive humanitarian crisis in West and Central Africa, ahead of Chad, Mali, Burkina Faso, Niger, the documents showed.

Nigeria is also grappling with a cost of living crisis that has seen inflation accelerate to its highest level in nearly three decades, propelled by skyrocketing food prices.

The UN has previously said Nigeria's northeast risks becoming a forgotten crisis as the humanitarian focus has shifted to crises elsewhere such as Ukraine, Gaza and Sudan.

A joint report by the government and UN in November said Nigeria faces one of its worst hunger crises with more than 30-million people expected to be food-insecure this year.

President Bola Tinubu's economic reforms, including scrapping a fuel subsidy and foreign exchange controls, have been blamed for worsening Nigeria's economic troubles. He says the reforms will put the economy on a stronger path to growth.