The "Business Call to Action" will bring together more than 80 chief executives of multinationals, and several - including Coca-Cola, Diageo, Microsoft, Sumitomo Chemical, Thomson Reuters and Vodafone - will present anti-poverty programs they have already undertaken.
"Over the next five years, the initiatives are expected to save almost half a million lives, create thousands of jobs, and benefit millions of poor people across Africa and Asia," the Department for International Development said in a statement.
The anti-poverty charity War on Want criticized the meeting as a "cynical public relations exercise" and accused some firms taking part, including Wal Mart and Coca-Cola, of having a poor record on workers' rights in Africa, Asia and Latin America.
"Instead of holding these companies to account ... Gordon Brown has allowed them to portray themselves as allies in the fight against poverty," John Hilary, War on Want's executive director, said in a statement.
"The prime minister should be working to address the poverty and human rights problems caused by business, not giving the companies a free ride."
The meeting, co-hosted by the head of the United Nations Development Programme, Kemal Dervis, is part of a push to meet the Millennium Development Goals - eight measures the international community agreed to take in 2000, with the aim of reducing global poverty by 2015.
"This year must be a year of action if we are to tackle the development emergency we face," Brown said in a statement. "Without an extraordinary effort, we will fail."
He said it was vital to enlist the support and expertise of global business "to develop new and innovative ways to spread growth, prosperity and opportunity in poor countries".
The UNDP's Dervis said the private sector was "one of the greatest untapped resources" in the fight against poverty.
"Businesses are engines of growth and sustainable development," he said. "Creative approaches and partnerships are essential in catalyzing vibrant new markets that can contribute to advancing inclusive growth and development."
