Dangote met with President Robert Mugabe in Harare in a rare sign of possible foreign investment for Zimbabwe, which has been in economic decline for more than a decade.

"We had a very, very good meeting with the president and I told him that we have already decided to invest in three areas, one is power, second one is cement and third one is coal," Dangote told journalists.

"We have already made up our minds to invest and so we are here and we will invest."

The Nigerian billionaire said he would spend close to $400m on the cement plant, which will produce a million and half tons of cement a year, making it the biggest in the country. He said the investment package would create jobs and "to help Zimbabwe to develop their own economy." Dangote is the head and founder of multi-billion dollar Dangote Group which has interests including cement production in several African countries.

The company also has major oil, gas, food and real estate investments across the continent.

Zimbabwe's economy has collapsed since Mugabe's land reforms of 2002, which broke the country's agricultural backbone.

Laws which require locals to hold majority stakes in all firms are also blamed for scaring off foreign investors. Many companies have closed, downsized or relocated. The International Monetary Fund said this year Zimbabwe's economic prospects looked "difficult", with growth falling again after a brief improvement.

Food shortages, rampant inflation, economic sanctions and disputed elections have added to the country's woes in recent years.