Rich countries told to start dishing out

Addressing the general assembly in New York on Tuesday, Mr Ban said he is "cautiously optimistic" that the Millennium Development Goals can be achieved if rich countries honour the financial commitments that they made at the UN Millennium Summit in 2000.

The goals included cutting extreme poverty by half, ensuring universal primary school education for all children, halting the Aids pandemic and reducing the proportion of people without access to safe drinking water and basic sanitation by half, all by 2015.

At the G8 summit in Scotland in 2000, France, Germany, Italy, Japan, Britain, the US, Russia and Canada agreed to increase yearly aid to developing countries, amounting to an extra $50bn (£32bn) by 2010 and channel $25bn (£16bn) of the increase to Africa.

According to the UN, that aid commitment is approximately $154bn (£100bn) in current value and an additional £23bn a year needs to be delivered to meet the target.

"If these promises are not met, the poor will suffer and, indeed, die in large numbers," Mr Ban warned.

"If we fail, the dangers in the world - instability, violence, epidemic diseases, environmental degradation, runaway population growth - will all be multiplied."

Mr Ban has invited world leaders to a summit at UN headquarters in New York on September 20-22, before the general assembly's annual ministerial meeting, to reinvigorate efforts to achieve the goals in the five years remaining.

The secretary-general said that some successes have been attained by the poorest countries, citing one of the largest-ever reductions in measles deaths in sub-Saharan Africa between 1999 and 2004 and the fastest growth in primary school enrollment in the same region within the past decade, from 58 to 74 per cent, mainly through the abolition of school fees.

In other successes, Malawi has doubled agricultural production, Cambodia halted and reversed the spread of HIV and Rwanda elected a majority of women to its parliament.

And in north-east Brazil, stunted growth - an indicator of child malnutrition - decreased from 22.2 per cent in 1996 to 5.9 per cent in 2006-7, according to the UN.

But Mr Ban said that "progress has been very uneven.

"We are off course because of unmet commitments, inadequate resources and a lack of focus and accountability," the UN chief told diplomats from the 192 UN member states.