In a report marking 25 years since the famine that killed around one million Ethiopians, Oxfam said that imported food aid saves lives in the short term but did little to help communities withstand the next shock.
The report, named Band Aids and Beyond, called on international donors to adopt a new approach focused on preparing communities to prevent and deal with disasters before they strike.
"Drought does not need to mean hunger and destitution," said Penny Lawrence, Oxfam's international director, who has just returned from Ethiopia.
"If communities have irrigation for crops, grain stores, and wells to harvest rains then they can survive despite what the elements throw at them."
Ethiopia has been hit by the food crisis affecting a large part of East Africa and the Horn.
Martin Plaut, Africa analyst
There is no doubt poor and erratic rains have hit the Ethiopian harvest. But large parts of the country have not been hit by drought. So why the current crisis?
It is in part the result of policies designed to keep farmers on the land, which belongs to the state and cannot be sold. So farms are passed down the generations, divided and sub-divided. Many are so small and the land so overworked that it could not provide for the families that work it even with normal rainfall.
At present only 17% of Ethiopia's 80 million people live in urban areas. Keeping people in the countryside is a way of preventing large-scale unemployment and the unrest that this might cause.
Last month Oxfam launched a $15m (£9.5m) emergency appeal for the whole East African region, where it is suggested that 23 million people in seven countries are under threat.
The WFP, which is also calling for aid to the region, says cuts in its funding have made it more difficult to feed people.
It says it is particularly concerned about Eritrea, where it is unable to collect data because of restrictions on movement.
The drought, brought on by four years of bad harvests, has been made worse by conflict, climate change and population growth.
BBC Africa analyst Martin Plaut says Ethiopian government policy banning land sales to keep people out of urban areas has also contributed.
All these other factors combined are at least as important as lack of rainfall, he says.
Fields of maize, burnt and withered by the sun, are the evidence of an emerging crisis, says the BBC's Mike Wooldridge in the Ethiopian town of Mekele.
The BBC's Mike Wooldridge returns to Ethiopia to view the impact of prolonged drought
In both the hardest-hit south of Ethiopia and in places in the north, farmers have told the BBC they face a total wipe-out of their harvests.
Some said they planned to sell their livestock, so damaging their livelihoods further.
Many aid officials say the figure of 6.2 million affected could rise further when the government makes its next assessment in mid-November.
On its website the WFP gives a figure of more than 10 million people in total affected by drought in Ethiopia.
The problem is compounded by high food costs, the WFP adds, with cereal prices doubling on many markets.
But the UN body's greatest concern is that there is currently no funding at all for a feeding programme to prevent moderately malnourished children from slipping into severe malnutrition and the risk of death.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.