The group called Africa "strategically important" and said the investments in New World Investments in Ghana and Pangaea/EMI Securities in Zambia gave the group an opportunity "to play a role in the exciting development of both countries' financial markets and their importance in the region as a whole".

It said: "Sub-Saharan Africa, excluding South Africa, is expanding rapidly.  There are world class businesses, just without world scale.  They need banking services."  So far, few have invested in local operations on the ground, with only Standard Bank of South Africa buying IBTC in Nigeria.

RenCap, however, has signalled its intentions to target the region by moving one of its most senior bankers, Andrew Cornthwaite, to oversee its existing operation in Nigeria.

Mr Cornthwaite, also head of RenCap's global investment banking, said: "As the financial centre of Sub-Saharan Africa, Nigeria is already experiencing rapid and sustainable economic growth, with an increasingly liquid and dynamic capital market.  This growth and development is poised to continue for several years."

Sub-Saharan Africa is gaining in importance for financial firms as the economies develop, often based on oil and gas discoveries such as in Nigeria and Ghana. The latter is also trying to position itself as the financial gateway to West Africa. Other countries interesting the banks include Kenya and Angola.

Companies have been slow to target the region because of a perception of political risk, uncertainty and a lack of Western resources and investment banks.

Mr Cornthwaite said: "The situation is similar to our experience in Russia 15 years ago.  There is a business opportunity here, and if you've seen the movie before, you're in a better position to capitalise," he said.

He continued: "The Nigerian market turns over $200m (£100m) a day.  We wouldn't be there unless we thought it would hit $1bn in the next five years."

Companies are looking to investment banks to provide debt and equity capital market operations, and increasingly mergers and acquisition advice, especially as the fragmented banking market consolidates.

Mr Cornthwaite said: "The sophistication is good in most of the existing African brokerages, although not all are up to international standard.  I'm suitably impressed."

Few international firms have invested on the ground.  Both Citi and JP Morgan operate on a "fly in, fly out" basis.  "There's not a flight I take, which doesn't have bankers coming into Africa, but they're always out that night," Mr Cornthwaite said.  He added that international competitors had been slow to target the region but were likely to target it within five years.