Africa is increasingly looking up to China for leadership at the global stage as opposed to the US, a new Gallup survey suggests.

Since the launch of its World Poll in 2005, Gallup says, approval for US leadership has been been strongest globally in sub-Saharan Africa, exceeding 75 per cent in many countries following Mr Obama's election nearly seven years ago.

The decline in recent years in support for the US role "is not mirrored by an increase in Africans' approval of China's leadership," Gallup points out. "Rather, Africans' attitudes toward China have remained relatively stable over the years."

In the most recent findings for 12 sub-Saharan countries, approval of the US role was greatest in Senegal, where 81 per cent offered a positive view. A 73 per cent share of Senegalese respondents also approved of China's leadership.

In Kenya, a slightly higher percentage of Kenyans approve China's leadership in comparison to that of the United States, a leading US opinion firm found in a poll released on Thursday August 6, 2015.

In the survey, which was conducted months prior to President Obama's visit to the east African country, 61 per cent of Kenyans expressed approval of Chinese leadership while 58 per cent approved of US leadership.

Support for the US role in the world has declined by 35 percentage points in Kenya since 2009, the Gallup company reported. Kenyans' approval of China's role rose five points during the same period.

But a larger share of Kenyans remain supportive of the US compared to Tanzanians and Ugandans, the poll shows.

In Tanzania, 49 per cent approve of US leadership -- a drop of 40 points over five years -- and 50 per cent endorse Chinese leadership, a drop of 14 points since 2009.

More Ugandans support the US role than that of China, Gallup found, with 48 per cent approving of Washington's leadership compared to 37 per cent of Ugandans who give an affirmative response to Beijing's.

In East Africa, Gallup noted in releasing the poll, the percentages of respondents who did not express an opinion ranged from 11 per cent in Kenya to 41 per cent in Uganda.

"Still," Gallup says, "this does not fully account for the declines in US approval in all countries such as Kenya, where approval dropped significantly and disapproval rose."

The firm does not suggest why Kenyans' attitudes toward US leadership have become far less favourable.

But the positive ratings in Kenya for the US following Mr Obama's election in 2008 were so enormous that a decline could be seen as inevitable.

Relations between the two countries did turn sour in the past two years. Many Kenyans resented US political intervention in the country's 2013 election, when Obama administration officials made clear that they did not want to see Uhuru Kenyatta elected president, due to his earlier indictment by the International Criminal Court. The ICC dropped Mr Kenyatta's case last December, clearing the way for improved ties between Nairobi and Washington.

Gallup says its poll results are based on face-to-face interviews with at least 1000 adults conducted every year between 2009 and 2014.

The margin of sampling error is said to range from 3.4 percentage points to 4.0.