Darfur, the Democratic Republic of Congo, Bosnia, Rwanda - all too often, the world's killing fields are recognised only belatedly, once death, disease and despair have taken their horrific toll. This week I had hoped to travel to Darfur to see for myself the realities on the ground. Unfortunately, the Sudanese government did not want me to visit. Of course what is most important is not my visit, but the continued suffering of the civilian population.

While Darfur is now headline news, aid workers around the world know that most crises fail to appear at all on our radars. Only a select few garner our attention. Indeed, neglected disasters are as persistent as they are pervasive.

How do we define "neglected"? Who is neglecting whom? By design or default? These questions are far from academic. Millions of people around the globe urgently need - and have a right to - humanitarian aid, but consistently fail to receive even minimum assistance. At a time when the rich world has never been larger or more prosperous, our response to human suffering remains both grossly inadequate and inequitable.

A disaster or crisis can be considered "neglected" when response falls short of the extent, duration or severity of humanitarian needs on the ground. Neglected crises encompass both singular events (war, earthquake) as well as recurring, smaller-scale disasters (drought, tropical storms) which exact a cumulatively high human and economic toll, and further undermine prospects for development.

As humanitarians, we pledge to provide assistance according to need, not creed, nationality, race or any other criteria. And yet we all know that some crises attract a far greater response than others, for reasons that have little to do with need.

If humanitarian need were the only determinant of assistance, then drought-stricken families in the Horn of Africa would not suffer in obscurity, nor would thousands of children in war-torn Ivory Coast go without clean drinking water. If need were the only criterion for our help, then the world's generosity during the tsunami crisis would be the rule, rather than the exception, for how we respond to all emergencies.

Sadly, crises in Guatemala, Guyana, and the Democratic Republic of Congo (DRC) last year again showed that underfunding and neglect was more common than magnanimity. Take Congo. In the six years from 1998 to 2004 some 3.9 million people there died from the effects of war - malnutrition, disease and displacement - in what is the world's deadliest crisis since the Second World War. Yet Congo's immense suffering has gone virtually unnoticed by the outside world.

In the last several years, UN funding appeals for Congo have received only slightly more than half of the amount required. Indeed, the word "neglect" only begins to hint at the degree of inequity that runs like a faultline throughout so much of the humanitarian landscape, be it Congo, Ivory Coast, Djibouti, Guatemala, Haiti and elsewhere.

Funding is not the only measurement of neglect, but it is the most quantifiable, and hence most commonly used. Over the years, humanitarian funding has remained insufficient relative to both needs on the ground and the growing wealth of the growing number of developed nations. Funding also varies widely - independent of need - across crises and sectors. Last year, for example, one out of every five UN Humanitarian Consolidated Appeals was less than 50 per cent funded, with the average appeal receiving only 66 per cent of required funding, as has been the case for the last six years.

We can and must do better in responding to human suffering wherever it occurs. Aid should not be a lottery, but a fundamental human right. We must move from lottery to predictability, so that all who suffer receive aid according to need, not creed, politics, or media attention.

The UN's newly launched Central Emergency Response Fund is an important step in this direction. It allocates one-third of its resources to core, life-saving activities in chronically under-funded crises. With $254m in current pledges, it is not a silver bullet. But it will help to rectify some of the imbalances which leave millions in acute need

Let's remember that behind every neglected crisis, there is a human face. The victims need to know their suffering is not forgotten, their story left untold. In the end, their story is also our own. Neglect ends where humanitarianism begins: with an acknowledgement of our shared humanity.

Jan Egeland is the United Nations under-secretary general for humanitarian affairs and emergency relief co-ordinator