"There is more than enough food in the world, yet today, more than one billion people are hungry," he told a high-level meeting on world food security that was meant to follow up on commitments made at the G8 summit in L'Aquila, Italy last July.
Reacting to a dramatic rise in food prices in early 2008, 26 countries and several international organizations gathered at the July summit pledged 20 billion dollars for coordinated support to country-led food security strategies.
They agreed to take long-term action to roll back world hunger and poverty through improving security, nutrition and sustainable farming.
"We must ensure that the money is disbursed promptly and effectively," Ban told Saturday's meeting which brought together leaders, ministers, experts and non-governmental organizations from nearly 100 countries.
The United Nations said food production must increase by 50 percent in order to feed the world's population in 20 years.
And climate change makes matters worse as UN experts estimate that every rise of one degree in average temperature at the earth's surface will translate into a 10 percent drop in farm output.
US Secretary of State Hillary Clinton, who co-hosted the event with Ban, underscored the drop in funding for agriculture caused by the priority given to emergency food aid.
But participants also heard about some encouraging success stories from Rwanda, with its president Paul Kagame explaining that thanks to irrigation projects and access to micro-credit for farmers: ""for three years we have realised food surplus."