Malaga signings banned over Osasuna debt
In a statement on their website, Malaga said the reason for the delay in paying was "the complexity of approving budgets and transactions with foreign entities" and added that funds would arrive soon to allow the payment to be made.
They did not say how much they owed Osasuna or what for, although local media reported it was linked to Malaga's purchase of defender Nacho Monreal in the close season.
"One of Malaga Football Club's priorities for the future is to improve the performance of financial budgets and cash flow," they said.
The club had received a cash injection of more than 120 million euros in the past year and had the personal guarantee of owner Sheikh Abdullah Bin Nasser Al-Thani, a member of the Qatar royal family, they added.
Malaga, who have targeted European qualification this season, are 10th in La Liga following Sunday's 4-1 defeat by champions Barcelona.