A day earlier Nigeria's aviation minister Hadi Sirika told reporters that the Dubai-based carrier had received most of its funds out of Nigeria and had about $35 million that still needed to be released.

Emirates declined to say how much was trapped in Nigeria, but a spokesperson said about half of the amount in its backlog was overdue for repatriation and that the process "remains beset with constant delays".

Nigeria is withholding $743 million in revenue earned by international carriers operating in the country, the highest amount owed by any nation, global airline industry association IATA said last week.

Sirika said on Thursday that the country was aiming to release money from foreign airlines' ticket sales, held up by dollar shortages in the country, but did not provide a timeline.

Nigeria is facing severe dollar shortages, forcing many citizens and businesses to seek foreign exchange on the black market, where its naira currency has progressively weakened.

President Muhammadu Buhari in February directed the central bank to increase the amount of foreign currency allocated to Emirates after the airline suspended flights to and from Nigeria because it was unable to repatriate funds.

The Emirates spokesperson said the carrier had made many concerted efforts to restart flights to Africa's most populous nation since halting them five months ago, but a solution continued to be stalled.

Oil is Nigeria's biggest foreign exchange earner, but rampant crude theft in the Niger Delta and years of under-investment have hit output and strained government finances. For a few months last year, Angola overtook Nigeria as Africa's biggest oil producer and exporter.