LAGOS, Nigeria — When an incredibly astute and prolific emerging market investor announced last year that there are at least 200 'hidden billionaires' in Africa unknown to wealth watchers, it didn't take long before Forbes beefed up its coverage profiling the super-rich in Nigeria. It's easy to see why. Among those who can be documented, Africa's richest man hails from here as do more than a quarter of the magazine's current top forty from the continent. Although economists rightfully keep talking about 'Africa rising', clearly there is at least one country that is floating closer to the top than the rest.

Ever since Nigerian fashion industry pioneer Omoyemi Akerele sat in conversation with Suzy Menkes last November at the International Herald Tribune's luxury conference, most insiders will have heard juicy tales about the voracious appetite and spending power of the country's well-heeled, well-educated and well-travelled upper classes. Akerele's scrupulous presentation made even the most sceptical in the audience take heed. Back in Lagos, Nigeria's commercial capital where she is based, Akerele has been instrumental not only in building up an impressive international market for indigenous fashion designers – by partnering with Selfridges, Pitti Immagine and the British Council – she is also a sounding board for international fashion executives looking to enter the local market.

"The luxury watch and jewellery retailers have held franchises for years for international brands like Cartier, Piaget and Rolex to name a few," says Akerele, founder of Lagos Fashion and Design Week and Style House Files, her consultancy firm. "The luxury segment receives the most publicity but of course the reality here too is that the percentage of people who can afford true luxury brands is significantly smaller than those buying in the middle and lower markets. However, due to lack of competition and higher margins, this segment ends up appearing more attractive. Nigerian-owned fashion design brands and international luxury brands such as Zegna and Hugo Boss are now operating in this realm."

As the continent's most populous nation, Nigeria's monumental scale helps to position it firmly in the centre of a much wider fashion stage covering virtually all demographic cohorts. To put its 174 million people into perspective, consider for a moment that there are more Nigerians than there are Japanese or Russians or citizens of any other country in Europe. It also means that one out of every five people in sub-Saharan Africa is a Nigerian. While it is true that more than half of Nigerians continue to live in abject poverty, the remaining 75 million who are upwardly mobile dwarf the entire population of South Africa as a diverse market force. Nigeria's main rival to the south can still count more wealthy residents; its overall economy is bigger; and its fashion market more developed. But Nigeria is fast picking up the pace.

"A real indication of the mass growth of the retail industry can be seen in the increase in number of successful online retailers like Jumia, Konga, 5^th and Quansah," says Akerele. "The Nigerian consumer is warming up to the idea of online retail thanks to order efficiency with the help of local debit and credit cards from financial institutions such as GTBank. And ASOS now also delivers to Nigeria, going against the stigma of internet fraud associated with Nigeria."

Jumia.com.ng and Konga.com both sell a small selection of merchandise from international fashion brands such as Calvin Klein, Diesel, River Island, Adidas, Zara, Forever 21, H&M, TopShop, Guess, Bulgari and Gucci.

Akerele continues: "The high street is also quite interesting. Mango has opened two branches within the country, in beauty MAC is rapidly expanding within the market and there’s talks of Maybelline too. At the lower end, South African brands, Mr Price and Pep are targeting the lower market as their niche and have an expansion plan of 50 stores in Nigeria."

What makes Nigeria such an exciting frontier market for consumer goods like fashion is that the fabulous wealth already reaped in the country – until now mostly by a tiny business elite close to government – pales in comparison to the country's potential to reap more by more ordinary residents. Thanks to its still epic oil reserves (11th biggest in the world), a booming new service sector and vast untapped mineral resources, the economy has grown by 6 percent each year for the last seven consecutive years.

Crucially, its reliance on petrodollars will wane as banking, telecoms and other new sectors flourish, helping wealth to trickle down to the 40 million or so who currently make up the middle classes. In the last five years alone, the number of middle class consumers in the country has already quadrupled – and if the African Development Bank's use of internet penetration as a proxy for middle class holds true, their numbers are set to continue growing. This, coupled with Nigerians' famous entrepreneurial spirit and characteristic resolve, should help new small businesses overcome some of same sorts of hurdles which global brands also face when operating here – endemic corruption, frustrating red tape and safety concerns over high crime rates chief among them.

Like so many other frontier markets, the lack of suitable commercial real estate, quality shopping centres or even well-defined retail districts is an obstacle which international companies find more immediately confounding. After private equity fund Actis compared the number of malls in Lagos, Nigeria to those in Johannesburg, South Africa, it found that although Lagos is more than twice as populous, there were only two international-standard malls of at least 20,000 square metres in Lagos while there were 74 in Johannesburg. Many are currently in the planning stages or under construction around the country.

But that didn't deter Ermenegildo Zegna, which recently made a landmark opening for luxury fashion brands. The firm's first flagship in sub-Saharan Africa is now in Lagos – Cape Town won't open until 2015. Because retail in Lagos is still mostly informal, inefficient and fragmented, opportunities for brave and determined brands like Zegna abound. Putting down a footprint early will increase its chances to yield substantial benefits later down the line – both in terms of brand loyalty and market share.

Online retailers like Jumia and Konga are also benefitting now that they have adapted to some of the local conditions which have kept most international online players – like Net-A-Porter, Yoox and Amazon – out of the direct delivery game to Nigeria. Konga's customers are allowed to pay cash on delivery because many Nigerians still don't have bank cards and because others are cagey of ecommerce due to the prevalence of online fraud and scams. An unreliable postal service and sprawling, gridlocked cities – often unnavigable by car in places – have meant that online operators built their own special courier fleets made up of motorbikes and auto rickshaws.

"Retail has long term prospects. As long as it's eventually backed with adequate infrastructure, effective distribution channels, relevant policies, manufacturing, stable electricity, stable political climate and all the rest of it, retail really is an opportunity for growth. Yes, Nigeria is a new market and, yes, doing business in Nigeria will be challenging. But it is well worth the risk," Akerele concludes.

If fashion brands, retailers and other players can avoid becoming daunted by the market's many initial barriers, there is scope for serious local expansion and a valuable testing ground for other countries around Africa . Many official figures for Nigeria – just like the country's number of billionaires – are vastly underestimated. But even taken at face value, they already add up to a very persuasive proposition at a time when some important Asian markets may not appear to be quite as immediately lucrative as they were once touted to be. For companies that can't afford not to take a longer view on new frontier markets, penetrating Nigeria in the short term may be a consideration they should take very seriously indeed.