The UN humanitarian agencies are seeking at least 451 million U.S. dollars to mitigate effects of El Niño, which is expected to affect between 2.7 and 3.5 million people in East Africa with its destruction to be felt in 2016.

A report from the UN Office for Coordination of Humanitarian Affairs (OCHA) Eastern Africa released in Nairobi on Friday says the region is prone to floods and drought even outside El Nino years.

"At least 451 million dollars is required to ensure preparedness and response to El Nino affected people in Ethiopia (174 million dollars shortfall up to the end of the year, 237 million dollars for prepositioning), Somalia (30 million dollars) and Kenya (10 million dollars)," OCHA said in its latest report.

Traditionally, El Nino had a variable impact on the region, ranging from ­foods affecting more than 3.4 million people in 2006/2007 to drought affecting more than 14 million people in 2009/2010.

According to the report, the 1988 ­foods affecting 2.5 million people and the 1999 drought affecting 31.5 million people were both associated with La Nina. The 2011 drought, which affected nearly 14 million people in the Horn of Africa, was also associated with La Niña.

"It is therefore imperative that countries continue their resilience programming for the most vulnerable, as well as preparedness and early warning activities even beyond this El Niño phenomenon," OCHA said.

The heavy rains are expected to displace, spread communicable diseases and hurt livelihoods as some regions have started experiencing floods already as governments and partners shift their focus to responses.

The aftermath of El Nino is set to increase the number of people in need of humanitarian aid to more than 21 million by the end of 2015 from about 11.4 million people at the beginning of 2015.

This funding shortfall comes on top of the existing Humanitarian Response Plans in the region, which have a collective funding gap of around 2.8 billion dollars.

"Humanitarian funding assigned for 2016 should be brought forward to allow for prepositioning, existing development funding should be reviewed for potential re-programming if needed," OCHA said.

The UN said disaster risk reduction and preparedness activities should continue beyond this predicted El Niño period.

"Historic patterns also show that a La Nina event sometimes follows El Nino, with an even greater overall humanitarian impact as coping capacities are eroded. An El Niña event, should it materialize immediately after this El Nino, will lead to a further deterioration in the humanitarian situation in the region," the UN said.

The report says countries in the region are already seeing the impact of the El Nino climatic event. Ethiopia reports an increase in food aid beneficiaries from 2.9 million in January 2015 to 8.2 million today.

Partners in Ethiopia are planning for 15 million people in need of food assistance by the first quarter of 2016.

Drier than average conditions are also affecting Sudan, Eritrea and Djibouti and the east of South Sudan. Localized ­floods caused by rains have already been reported in parts of Somalia, Western Kenya and at the Kenyan Coast.

According to OCHA, the number of food insecure people in the region is expected to increase by 83 per cent, from approximately 12 million people at the start of 2015, to 22.1 million people by the start of 2016.

Severe and moderate acute malnutrition among children has significantly increased in Ethiopia, Somalia, South Sudan and this trend is likely to persist over the coming months.

"For countries expected to be hit by drought, immediate scaling up of preventive and curative nutrition programs targeting both the moderate and severely malnourished is critical," it said.

"Governments and humanitarian partners are racing against the clock to prepare for floods caused by El Nino. Sub-national preparedness, prioritization, stockpiles and logistics are key," OCHA said.

It said regional coordination to address cross-border aspects of floods and droughts, such as displacement and humanitarian access, and livestock vaccination should be a priority.

The peak strength of this El Nino, expected between October and January 2016, coincides with the short rainfall season (October-December) in most countries in the Horn of Africa region and there is an expectation of enhanced rainfall in the south-western parts of the region.

"Somalia and Kenya are preparing for possible foods and ­food-related displacement. On the other hand, arid and semi-arid areas could also see favorable pasture, crop development and marginal agricultural conditions due to enhanced rainfall, useful for rebuilding livelihood assets of the pastoralist communities," OCHA said.