The four banks that promised the ailing Swissair Group a cash injection of SFr1 billion have yet to deliver the funds, according to the "SonntagsZeitung" newspaper.
The contract announced by Swissair's new chief executive, Mario Corti, has not been signed by Credit Suisse, Citibank and Deutsche Bank because a "number of strict conditions have not been fulfilled," the Sunday paper reported.
Switzerland's biggest bank, UBS, pulled out of the deal, saying the loan was too risky.
The banks have called on Swissair Group to withdraw from its stake in the beleaguered Belgian carrier, Sabena. Swissair currently holds a 49.5 per cent stake in the company.
The banks are also reportedly asking Swissair to stop financing the loss-making French airlines AOM and Air Liberté.
Last week, Corti said that Swissair "did not intend to use the banks' credit", which was "above all an insurance."
Swissair Group reported losses of SFr2.9 billion last year after an aggressive alliance strategy with other national carriers helped plunge the company into financial turmoil.
swissinfo with agencies