Nigeria is withholding $743 million in revenue earned by international carriers operating in the country, the highest amount owed by any nation, a spokesperson for the global airlines industry association said on Thursday.

Nigeria faces severe shortages of foreign currency, leading to restrictions on imports and meaning investors cannot convert local currency to repatriate their profits.

International Air Transport Association (IATA) spokesperson Katherine Kaczynska said governments around the world owed $2.2 billion to airlines. Nigeria had the highest amount of blocked funds, followed by Algeria and Lebanon, which owed $165 million and $146 million respectively.

"Enabling the efficient repatriation of revenues is critical for any economy to remain globally connected to markets and supply chains," Kaczynska said in emailed response to questions from Reuters.

Dubai's Emirates suspended flights to Nigeria last year after failing to repatriate ticket sales. Last month, President Muhammadu Buhari directed the central bank to increase the amount of foreign currency allocated to Emirates after speaking to UAE President Sheikh Mohamed bin Zayed Al Nahyan.

Emirates has yet to resume flights to Nigeria, which is Africa's most populous nation and is responsible for a large share of the continent's air travellers.

Industrial-scale theft of crude of oil, Nigeria's single biggest earner of foreign exchange, has greatly reduced the country's flow of dollars in the last year.

Apart from Nigeria's $743 million debt, Kaczynska said countries under the West African Economic and Monetary Union owed $132 million while Zimbabwe, which has perennial dollar shortages owed $80 million.

Reuters