A massive rise in the number of malaria cases in Ethiopia has raised fears of a major epidemic in the impoverished Horn of Africa nation, the United Nations said Monday, adding that medical services were ill-equipped to deal with the situation.

"A sharp increase in malaria cases and deaths across Ethiopia is raising fears of a major epidemic," the UN Office for the Coordination of Humanitarian Activities (OCHA) in Ethiopia said in a statement.

The more than 20,000 reported cases countrywide in June was 10 times higher than in the same month last year and was an ominous portent for the current malaria season which runs from June to October, OCHA said.

Of those, 21 cases have been fatal with the death toll rising to 42 if May is factored in, it said, adding that the worst affected areas were Tigray, Amhara, Oromiya, Afar, Somali, Benshangul-Gumuz and the Southern Nations Nationalities and People's regions.

It provided no state-by-state breakdown but said it was working with Ethiopian officials to distribute medicine and insecticide-treated mosquito nets in the affected areas.

At the same time, it cautioned that the 2.5 million doses of the CoArtem treatment and nets "currently in the country will fall short if there is a major epidemic."