Health experts say most of the one million deaths caused annually by malaria occur in Africa, costing the continent more than $12 billion every year.
In one region in the north of Ethiopia, authorities recorded 20,000 cases in June, a 10-fold increase from the same month last year, accompanied by 21 deaths.
The most worrying figures were from the Tigray, Amhara, Oromiya, Afar, Somali, Benshangul-Gumuz, and Southern Nations Nationalities and People's regions, the U.N. Office for the Coordination of Humanitarian Activities (OCHA) said.
More than 2.5 million doses of malaria-battling drugs have been imported and almost 900,000 doses distributed to the worst-hit areas, OCHA said.
Most malaria infections in Ethiopia are contracted between the months of June and October. The disease is prevalent in 75 percent of the Horn of Africa nation, with five million cases reported per year, according to Ethiopia's ministry of health.
The U.N.'s World Health Organisation is carrying out an assessment of conditions in the affected regions and is working with UNICEF to provide the government with logistical support.
Ethiopian health authorities say they fear supplies of drugs and insecticide-treated mosquito nets will fall short of demand if there is an epidemic.
The widow of a victim of malaria near Bedele, Ethiopia, in 2004. A massive rise in the number of malaria cases in Ethiopia has raised fears of a major epidemic, the United Nations said(AFP/File)