Interbank lending tension is serious: ECB economist

"Banks in certain regions of the eurozone prefer to deposit their surplus cash with the ECB rather than lending it to other banks. We take these signals seriously," Stark told the German business daily Handelsblatt.

Eurozone banks parked 90.5 billion euros ($129.3 billion) with the ECB overnight from Thursday to Friday, an increase from the previous day and the highest level since August 8 when it was 145.2 billion.

Stark noted however that "the situation is not comparable to that in the autumn of 2008 after the failure of Lehman Brothers," a US investment bank that went bankrupt in September of that year, with the result that a year-old financial crisis then became a global economic crisis.

Interbank lending markets seized up at that point, forcing central banks to open the cash taps.

Stark also expressed scepticism regarding the chances of a so-called eurobond being created to help heavily indebted eurozone governments.

Common bonds "are a transfer union" that some in the eurozone, especially Germans like Stark, have repeatedly warned against.

Goldman Sachs economist Dirk Schumacher noted a survey by the German polling institute Emnid that found 76 per cent rejected the introduction of eurobonds, while 15 per cent were in favour.

Some 37 per cent of those polled felt that bringing the Deutsche Mark back would be a good idea.

Critics of a transfer union say it would simply allow those who have run up heavy debts to obtain financing from others who have scrupulously balanced their own accounts, and weaken pressure on the former to get their finances in order.

"It's a face-saving solution that sends the wrong signals," Stark commented.

"We would need a European constitution with sovereignty transfers from all countries. Only then would eurobonds mean anything," the economist added.