Speaking at the two-day European Development Days gathering in Brussels, Miliband said the world faces a “triple migration emergency”.
This includes a “crisis of toxic politics” in countries that are seeking to “push back” on efforts to tackle asylum and migration issues.
“These countries refuse to accept the idea that they have a responsibility in this area,” said Miliband, now CEO of the International Rescue Committee.
“What we are seeing is an unprecedented retreat from multi-lateral engagement.”
A second “crisis”, he told the EDD event, is the huge growth in people fleeing crisis-torn countries and conflict zones, like Sudan, Syria, Iraq and Lebanon.
The third, he said, is that the humanitarian sector itself is not working as “effectively” as it could to address the issues.
The former Labour cabinet minister said the three crises were hampering the international community’s ability to make sufficient progress in tackling inequalities, migration and displaced persons.
Speaking in a session on the relationship between mobility and inequalities, Miliband also voiced concern about the UN’s sustainable development goals (SDGs).
He said the much-vaunted SDG targets did not directly address immediate needs such as the health of refugee children.
“What we are seeing is an unprecedented retreat from multi-lateral engagement” David Miliband, Former UK Foreign Minister
“Where there are no such targets there is no drive to do something about the problem.”
He said he hopes that an upcoming SDG summit in September will set new and specific targets.
Miliband also expressed concern about the killing of an IRC member at the weekend.
Staff member Seydou Zakari was killed on Saturday in an attack of Tcholori village, in eastern Niger.
The driver of their vehicle, an IRC contractor, was also killed. Zakari was visiting the village, located about 20 miles outside Diffa, to check on the construction of a borehole, part of a life-saving water programme for communities in eastern Niger.
Miliband said, “These deaths are a tragic reminder of the risks IRC and other humanitarian staff face every day, as they seek to deliver life-saving programs for people affected by crisis and conflict.”
Miliband was the keynote speaker at the 13th edition of the European Development Days, the forum on development cooperation.
The event will host more than 8,000 participants from 140 countries worldwide, representing 1,200 organisations from the development community.
This year's theme is ‘Addressing inequalities: building a world which leaves no one behind'.
It will debate successes and failures in addressing inequalities in the context of the 2030 Agenda and the implementation of the SDGs.
The event heard that despite some progress, inequality is still a major impediment to sustainable development, limiting life chances by restricting access to everything from education and healthcare through to energy and sanitation.
For example, an estimated 19.9 million children still do not receive the required three doses of the DTP (diphtheria-tetanus-pertussis) vaccines during the first year of life.
Also speaking at the event, European Commission President Jean-Claude Juncker said: “In these turbulent times, the EU is a force for good in this world and a reliable partner for all. We are the world's largest development donor, but this is not charity, it is investment. Investment in growth, jobs and in building a better future for young people across the globe.”
Fifteen young leaders from around the world are also attending the EDD to debate inequalities and exchange ideas and experiences with world leaders and key policymakers.