"Africa is becoming the next frontier, perhaps the last frontier," Ethiopian Airlines Chief Executive Tewolde Gebremariam told Reuters at the ITB travel fair in Berlin, saying its planes were full of Chinese investors.

Hotel chain Marriott (MAR.N), for example, is opening new sites this year in the Rwandan and Ghanaian capitals of Kigali and Accra, and it plans to double the number of hotels it has in Africa and the Middle East to 100 over the next five years.

"We've been trying to get into Africa for 15 years, but the issue was financing," Ed Fuller, international director at Marriott, told Reuters, saying that the wave of investment from China and elsewhere was making opening new hotels much easier.

Rival Carlson has just opened a new Radisson Blu hotel in Ethiopian capital Addis Ababa, the seat of the Africa Union and therefore a hub of political activity.

"We are looking more at investing in sub-Saharan Africa, especially the oil-producing countries," Chief Executive Hubert Joly told Reuters, citing Ghana and Nigeria as examples.

International arrivals in sub-Saharan Africa grew by 7 percent in 2011, outpacing global growth of 4 percent, according to the United Nations World Tourism Organisation.

Overall African arrivals were flat, though, as the Arab Spring revolutions caused a drop in travel to North African countries such as Libya and Tunisia.

Oil-rich Libya, however, has been a hotspot for those seeking new investment as the country rebuilds itself after the fall of Gaddafi.

Joly said the group's Tripoli hotel was doing extremely well, while Marriott's Fuller described the potential for the hotel industry in Libya as phenomenal.

It's not just about oil, though. The underdeveloped African market is also of interest to western retailers, with U.S. group Wal-Mart (WMT.N) having bought a majority stake in South African retailer Massmart.

Ethiopian's Gebremariam said investors in the infrastructure and agriculture sectors were flying in from all over the world, and the growth opportunities were tempting airlines, too.

"With the economic slowdown in Europe and the United States, more and more European and American carriers are focusing on Africa," Gebremariam said, citing Air France-KLM (AIRF.PA) and Lufthansa (LHAG.DE).

(Reporting by Victoria Bryan and Maria Sheahan; Editing by Will Waterman)

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