The UN World Food Programme will feed fewer than 100,000 of 6.5 million needy dependants in the sheltered communist state until shipments from the United States, Russia and others begin to arrive at the end of March, the WFP coordinator in Pyongyang, Masud Haydar, told a news conference.
Orphanages had already cut back from three meals a day to two, he said.
Underweight pregnant mothers were more likely to give birth to poorly developed babies and elderly people on small pensions would be unable to buy food on fledgling markets where prices had skyrocketed, he added.
"If you're going to give, please give early," Haydar urged foreign countries.
He held out hopes a second round of six-nation talks on the North Korean nuclear crisis later this month in Beijing could produce a turnabout. But without new pledges, the WFP food pipeline would dry up again in June.
"I'm afraid with this increasingly erratic pattern, the painstaking gains that the humanitarian community, including the WFP, have made in pushing back, improving the nutritional situation ... will be lost," he said.
"People are not really expected to die because of short-term deprivations," he said, but added: "People in fragile and recovering health ... would then again suffer a setback."
"If you're going to give, please give early"
He said the food crisis came at the wrong time - in the dead of winter, when stocks from the October harvest were already depleted and at a point when embryonic economic reforms had driven food prices up on farmers' markets.
In 2003, breaks in the pipeline forced the WFP to stop feeding as many as half of its dependants who constitute more than a quarter of the North's 23 million people.
"Now we're talking of a total cutback," Hyder said. "It's graver, with deeper consequences."
Haydar has acknowledged the lack of funds is symptomatic of international frustration with restrictions Pyongyang puts on the WFP, which lacks access to about 40 of 206 counties.
He appealed to the North to lift the constraints, but stressed gradual progress had been made on that front.
WFP is seeking 485,000 tonnes of commodities in 2004, but has been pledged only 140,000 tonnes - a small fraction of which has arrived.
Haydar said it remained to be seen whether the North's neighbour and ally China, which sends food estimated at about 200,000 tonnes across the border each year, might consider channelling aid through the WFP.
The WFP will phase out aid to China by the end of 2005 and has said it wants China to become one of its major donors.
Food shortages have plagued North Korea since at least 1995, when it first appealed for aid after floods compounded years of economic mismanagement and the disintegration of its main patron, the Soviet Union.