At the conference, Oxfam, ROPPA (Network of Farmers' and Agricultural Producers' Organisations of West Africa) and the Roll Back Malaria (RBM) Partnership will ask donors, governments in the region, regional bodies, non-governmental organisations and United Nations agencies to close the funding gap.
They will also be asked to keep regional markets open to keep food flowing and prices down, to strengthen leadership and co-ordination to ensure an effective response, and to invest in the long-term to build resilience and break the hunger cycle, the Oxfam spokeswoman said.
The hunger season is starting now. Families cannot wait any longer for action; there are too many already being pushed over the brink.
There is a massive funding gap in this response and the governments can make all the difference in helping meet these immediate needs and also, longer term, in breaking the hunger cycle in the Sahel.
A funding shortfall of more than £570 million will be addressed at a conference aimed at saving millions of hungry children and families across West Africa.
Donors attending Oxfam's pledging conference in Brussels on Monday will look at the work needed to tackle the food crisis in the Sahel, which covers northern Senegal, the southern part of Mauritania, Mali, the southern part of Algeria, Niger, Chad, the southern part of Sudan and Eritrea.
More than 18 million people are facing hunger across West Africa, but aid agencies are warning that, with the hunger season approaching, many lives are at stake if donors do not step up, an Oxfam spokeswoman said.
The former Tory Chancellor Lord Lawson has welcomed the Government's u-turn on the charity tax.
He said he believes the Chancellor George Osborne has "taken his eye off the ball" in this case, in part because of the need to negotiate everything with his Liberal Democrat Coalition partners.
He told BBC Radio 4: "The great thing is that George [Osborne], on charities in particular which in my judgment was the most important thing - the biggest error, he has done the right thing and has had the courage to do the right thing. I am delighted."
Chancellor George Osborne has conceded that the proposed plans to cap tax relief on charitable donations would have damaged charities.
Roland Rudd, Founder of Legacy 10, an independent campaign that encourages charitable giving has praised Jeremy Hunt for his role in the Government's u-turn on charity tax.
Great news for Legacy10 campaign that charity tax cap scrapped; a personal victory for Jeremy Hunt who listened to philanthropists
Controversial plans to cap tax relief on charitable donations have been scrapped by Chancellor George Osborne.Read the full story ›
A major Tory donor who withdrew his support for the party over the charity tax relief proposals welcomed today's U-turn.
Venture capitalist Jon Moulton, who has given the Conservatives £300,000 since 2004, told BBC Radio 4's World At One: "The idea that we charge into the sources of income for charities without very much thought was just not right.
"It was a bad decision. I am pleased they have had the nerve to actually reverse it.
"It seems to reflect a lack of proper consideration before the stuff was put out. Nobody had thought through the implications of doing it."
David Bull, the Executive Director of UNICEF UK, has welcomed the Government's u-turn on the charity tax. He said:
Today’s Government announcement on charitable tax relief is great news for vulnerable children. Donations from wealthy people are hugely important to UNICEF UK during humanitarian emergencies and this announcement will mean that we can continue to respond quickly, such as in the current food crisis in West Africa where one million children are at risk of severe malnutrition. The announcement shows the Government has been listening to charities during the consultation and we very much welcome today’s decision.
Labour has accused George Osborne of trying to "bury bad news" by unveiling his latest climbdown while Culture Secretary Jeremy Hunt was giving evidence to the Leveson Inquiry.
"This decision has already done considerable damage and has been responsible for the toughest year in a generation for Britain's charities and community groups.
"If ministers understood the work charities did, the vital difference they make for some of our most vulnerable and the important contribution they offer to make our communities stronger, this policy mess could have been avoided.
"Instead we have the spectacle of George Osborne trying to bury bad news on the day one of his rivals is in hot water at the Leveson Inquiry."