A massive infestation of locusts swept the southern Sahel last year, destroying much of the harvest. This combined with drought has led to severe food shortages across the region, but has hit Niger - the second poorest country in the world - the hardest.
The British Red Cross will provide immediate food relief to the most vulnerable and distribute seeds, which must be planted by the end of the month to ensure a harvest in October.
Funds raised will help set up additional feeding centres across the region to reach more than 200,000 people affected.
The French and Spanish Red Cross are also assisting national Red Cross societies in the region to thwart the massive humanitarian crisis.
An estimated third of the 13 million Niger population desperately need food, among them 800,000 malnourished children.
It is feared one in ten children in the worst affected areas in Niger could die unless they get urgent help.
In Mali, 20 per cent of the population - around one million people - are affected by the food shortages.
The crisis is also affecting about 750,000 people or 26 per cent of the population in Mauritania and 500,000 people in Burkina Faso.
Hundreds of families are roaming the parched desert, which is littered with cattle carcasses, desperately seeking help.
Although rain has improved the prospects for this year's harvest, it also brings with it the risk of malaria and diarrhoea.
It is also vital that people get seeds and money for livestock, tools and fodder, to prevent the next harvest from failing.