US Treasury deputy secretary Neal Wolin was in South Africa this week, meeting Treasury officials and the Reserve Bank's newly appointed governor Gill Marcus - following his visits to Rwanda and Tanzania.

Chinese premier Wen Jiabao landed in Egypt on Friday for the Forum on China-Africa Co-operation, a summit with African leaders.

Wolin's trip represented the US's intensified interest in Africa under President Barack Obama. But the US interest is considered benign, while China's has been seen as more intensive and, arguably, colonising.

Wolin, though, said the US did not view China as competition in Africa.

"There is plenty to be done and there is room for us and others to come in."

He did, however, say that the US was asking China "for transparency and the application of global standards" in its dealings in Africa.

China's investment in Africa has risen exponentially in recent years.

Direct Chinese investment in Africa was $7.8-billion last year, up from $491-million in 2003, while two-way trade has increased tenfold (from just more than $10-billion) since the beginning of the decade. Last year it rose 45% to more than $106-billion, making China a bigger trade partner than the US for the first time.

Wolin said the US focus was on infrastructure, agriculture and food security, and financial access

"Poor infrastructure, particularly in the power and transport sectors, remains a key growth constraint in most if not all sub-Saharan African countries."

He said agriculture on the continent was also "desperately in need of smart investment", while expanding access to credit and other financial services would be essential as African countries sought to promote the growth of small businesses.

Wolin said: "The shift towards the G20 reflects the critical importance of emerging economies like South Africa, India, Brazil and others."

The areas where partnership and co-operation between the US and South Africa were important were financial regulatory reform, the rebalancing of the global economy and economic development in Africa.

Many economies had an outdated approach to regulation and were incapable of managing the risks inherent in the 21st-century global financial system, Wolin said. SA had a significant role in this process. It came to the table with credibility, its banks were solvent and well managed and had little exposure to toxic assets, and financial regulation was strong, Wolin said.

While China was leading talks with African leaders at the weekend, it and the US were not the only ones increasing their presence in Africa.

There has been huge interest from countries such as Brazil, whose annual trade with Africa rose to more than $26-billion last year from $3-billion in 2000.

Indian trade with Africa has increased similarly, and India invested in the most projects on the continent last year.

Countries and companies are largely interested in Africa's resources, but are increasingly interested in land for agriculture to produce food.

Reuters reported that China's direct investment in Africa, excluding the financial sector, rose 79% to $875-million in the first half of this year. One of the biggest single investments remains the Industrial and Commercial Bank of China's stake in Standard Bank.