Zimbabwe faces a growing food supply crisis, with a $290 million shortfall in funding desperately required to feed up to 4.5 million people in need by next year, the United Nations warned Monday.

A regional drought worsened by the El Nino weather phenomenon has hit Zimbabwe hard, with Mozambique, Zambia and Malawi also affected as thousands of cattle die, reservoirs are depleted and crops destroyed.

"The general outlook is the food security situation in Zimbabwe from now right up to March 2017 is bleak," UN World Food Programme (WFP) country director Eddie Rowe said at a media briefing in Harare.

"Rains received in March-April have marginally improved the situation. For most, however, it was too late to revive failed crops. There are quite a number of districts that are still feeling the full brunt of El Nino."

President Robert Mugabe in February declared a state of disaster in rural areas hit by drought in Zimbabwe, where the moribund economy has worsened the shortages.

"Of the required $360 million in the response plan, approximately $70 million has, thus far, been received," United Nations Development Programme representative Bishow Parajuli said at the briefing.

"People in need will increase and food insecurity in the rural population will fluctuate from 30 percent in April to 49 percent -- approximately 4.5 million -- during the peak of the lean season from January to March 2017."

A regional drought report by the UN's Office for the Coordination of Humanitarian Affairs (OCHA) said Monday the acute child malnutrition rate in southern Zimbabwe was the highest in 15 years at 2.3 percent.

"Children are dropping out of school and waking up in the middle of the night so that they can find and collect clean water," the report said.

"In Zimbabwe, 6,000 children in Matabeleland North have dropped out of school, citing hunger and the need to help out with house or farm work."

A former breadbasket, Zimbabwe has suffered perennial shortages in recent years and has relied on importing grain from neighbouring countries.

Last week, wildlife authorities asked local farmers and private game rangers to buy wild animals to save them from starvation in national game reserves.