Starving people in drought-stricken west Africa are being forced to eat leaves and collect grain from ant hills, say aid agencies, warning that 10 million people face starvation across the region.

With food prices soaring and malnourished livestock dying, villagers were turning to any sources of food to stay alive, said Charles Bambara, Oxfam officer for the west African region.

"People are eating wild fruit and leaves, and building ant hills just to capture the tiny amount of grain that the ants collect inside.

"The situation here in Chad is desperate. There is not enough food in the country, over 2 million people here are not getting enough," said Bambara.

In Niger, which the United Nations classifies as the world's least developed country, starving families are eating flour mixed with wild leaves and boiled plants.

More than 7 million people – almost half the population – currently face food insecurity in the country, making it the hardest hit by the crisis.

According to UN agencies, 200,000 children need treatment for malnutrition in Niger alone.

"Niger is at crisis point now and we need to act quickly before this crisis becomes a full-blown humanitarian disaster," said Caroline Gluck, an Oxfam representative in the country.

With food prices spiralling, people are being forced to slaughter malnourished livestock, traditionally the only form of income.

"When you walk through the markets, you can see that there is food here. The problem is that the ability to buy it has disappeared. People here depend on livestock to support themselves, but animals are being killed on the edge of exhaustion, and that means they are being sold for far less money. And on top of that, the cost of food basics has risen," explained Gluck.

Compounding the crisis, thousands of animals have starved to death as villagers use animal fodder to feed themselves.

Oxfam has launched a £7m emergency appeal to try to avert a humanitarian catastrophe, after failed harvests and widespread drought brought severe hunger and malnutrition across the region. Save the Children has launched a separate £7m appeal.

"This is just the beginning of the traditional hunger period, and people have already been forced to sell their livestock. This is very early for the alarm bells to be ringing, before Niger has even reached the start of the most critical part of the food calendar. You can imagine three to four months down the line how shocking the situation will be," said Gluck.

"Yesterday I saw women sifting through gravel at the side of the road, trying to find some grains that may have been blown from aid trucks," said Gluck, as hungry and impoverished villagers flocked to the country's capital, Niamey, in search of food.

Gluck has likened the developing situation to that of the 1984 famine in Ethiopia, during which an estimated 1 million people died due to drought and a slow response to the crisis both within the country and internationally.

"West Africa has traditionally not been very high on the developed world's priority list. The question now is how many people do we have to see die before the world will act?" she said.