VANCOUVER - A United Nations envoy examining homelessness in Canada wants the federal government to launch a 10-year program to build social housing.

Miloon Kothari makes the recommendation in his preliminary report. He says his two-week, cross-country investigation produced shocking evidence on the number of homeless in Canada and the conditions endured by aboriginal people on and off reserves.

Kothari is harshly critical of federal inaction on homelessness, noting Liberal and Conservative administrations have reported multi-billion-dollar surpluses.

His report notes a Canada Mortgage and Housing Corporation surplus of almost $1 billion and he says that makes the housing crisis even more striking.

Kothari presents his final report to the United Nations Human Rights Council next year.