Nigeria's central bank has made an additional payment of $64.44 million of verified foreign exchange backlog owed to airlines, bringing total payments to $136.73 million, a spokesperson said on Tuesday.

Africa's biggest economy has about $7 billion in forex forwards that have matured, a major concern for investors as foreign currency shortages continue to weigh down the naira currency, despite assurances by the Central Bank of Nigeria (CBN) to clear the backlog.

About $2.5 billion of the backlog across sectors such as manufacturing, aviation and petroleum has been paid.

CBN spokesperson Hakama Sidi Ali said all the verified claims by airlines, which sold tickets in the local naira currency but have been unable to get their money out of the country, had now been cleared.

"The Governor, Olayemi Cardoso, and his team were doubly committed and would stop at nothing to ensure that the verified backlog of payments across all other sectors was cleared and confidence was restored in the Nigerian foreign exchange market," Ali said in a statement.

Foreign airlines were owed more than $700 million at the end of November.

(Writing by Elisha Bala-Gbogbo, editing by Ed Osmond)