Levels of economic disparity in major US cities, including New York and Washington DC, are comparable to those of African cities, a United Nations report has concluded.

The UN-Habitat report "State of the World's Cities" released on Thursday said that, while the US has less poverty than many cities in the developed world, inequality is high, rising above the international "alert" line.

It said race was a key factor for US economic inequality.

"The life expectancy of African Americans in the United States is about the same as that of people living in China and some states of India, despite the fact that the United States is far richer than the other two countries," it said.

In one example, the report cited figures from western New York state, where 40 per cent of black, Hispanic and ethnically-mixed households earned less than $15,000 in 1999, as compared to 15 per cent of white households.

Beijing 'most equal'

The most balanced city, both in Asia and in the world, is Beijing, the capital of China,  whereas the least egalitarian in Asia is Hong Kong, the Chinese-administered former British colony, the report found.

The world's most equal cities are located, on average, in western Europe, it said.

Denmark, Finland, the Netherlands and Slovenia were among those with the lowest levels of inequality, it said.

In Latin America, Brazilian cities "have the greatest disparities in income distribution in the world," the UN repot said.

Brazil is struggling to control rising unemployment and declining wages.

Cities in sub-Saharan Africa have the world's highest levels of urban poverty, with more than half of city residents living below the poverty line.

The report also said cities in South Africa and Namibia continue to have extremely high levels of income inequality, despite the end of apartheid early in the 1990s.