The World Food Programme said on Friday that it is preparing to provide food aid to 1.1 million Zimbabweans before the next harvest in 2019, as rural smallholders face shortages.
Growing food prices and the country's dire economic state could also affect those living in urban areas, the UN food agency added.
"WFP plans to address the most urgent food security needs of 1,135,500 people during the peak of the 2018-19 lean season," said the agency's Zimbabwe spokeswoman Ashley Baxstrom in a statement.
"Vulnerable groups are always disproportionately affected by adverse conditions (and) shocks."
The WFP said that $71.2 million (61.1 million euros) would be needed for the planned response, with $22 million already raised -- largely from USAID.
The Zimbabwe Vulnerability Assessment Committee's 2018 Rural Livelihoods Assessment Report suggested that more than 2.4 million people will be food insecure during the peak of the 2018-19 lean season.
The WFP's statement follows a report by the Famine Early Warning Systems Network which said poor families in arid areas of Zimbabwe are running out of food.
"These food security outcomes are expected to persist through March 2019," said the network on its website.
Livestock conditions were also deteriorating across the country due to water shortages and poor pasture, it added.
Zimbabwe is battling an economic crisis that includes cash shortages, high unemployment and lack of investment which has caused the cost of imported food to soar.
Newly-inaugurated President Emmerson Mnangagwa has vowed to fix the country's economy after he was sworn in following July 30 elections, the results of which were disputed by the main opposition party.